text:
The PAGAC's final step in developing this report was to integrate and
summarize the key conclusions and supporting data that each subcommittee
prepared and presented in their chapters (Part G: The Science Base).
Each chapter in Part G
provides a review of the scientific literature on physical activity and a
selected health outcome or population, and the chapters' conclusions are
supported by original publications cited in extensive reference lists.
Each subcommittee's major conclusions were reviewed and accepted by the
PAGAC during its final meeting on February 28-29, 2008. Because much of the
scientific review by PAGAC members and consultants was organized around
specific health outcomes, the PAGAC decided that it needed, where possible, to
integrate key findings for these various outcomes into general statements about
the scientific support for health-related benefits of physical activity. This
chapter provides the results of the Committee's summary and integration
process. Using a plan outlined below, PAGAC members first summarized the type
and strength of evidence for their major conclusions. This evidence is
presented in a series of tables on pages E-4 to E-22.
The Committee then integrated the evidence and conclusions by
developing responses to a set of questions that are typical of those raised by
health and fitness professionals and the general public about the scientific
evidence on a number of issues about physical activity and health. These
responses are supported by the information provided in the chapters in
Part G: The Science
Base. The questions and answers can be found on pages
E-22 to E-35.
During the final PAGAC meeting, each subcommittee chair was asked to
prepare a summary of key findings for discussion by the Committee, using the
plan outlined in Table E.1. Each
subcommittee's summary report was to include information on the type and
magnitude of evidence reviewed, the strength of the evidence, characteristics
of the physical activity most likely to produce the outcome, any evidence of a
dose response, and any evidence that being sedentary puts a person at high risk
(see Table E.1A). To determine the overall
strength of the evidence for major health and fitness outcomes and to evaluate
the issue of dose response for these outcomes, subcommittees considered the
types of studies that addressed each specific question (see
Table E.1B) and the general quality of these
studies (e.g., design, sample size, statistical power, measurement methods,
follow-up, adherence). For each major outcome, but not for each study,
subcommittee chairs were asked to assign a strength of evidence — strong,
moderate, weak — based on the evidence they included in their review
chapters (see Table E.1C). Also, in assigning the
strength of the evidence, subcommittees included factors that support a causal
relation between physical activity and a specific outcome, such as evidence of
favorable changes in biomarkers considered to be in the causal pathway or a
significant dose-response relation.
A. Instructions to Subcommittee
B. Types of Evidence
C. Strength of the Evidence
While deciding on a plan for summarizing the evidence, PAGAC members
discussed the possible use of an evidence-based rating system designed for the
development of evidence-based guidelines for medical practice, such as those
adopted by the American College of Cardiology and the American Heart
Association in 2006 (1). This approach was dismissed for
several reasons. First, a full application of these methodologies did not apply
to the PAGAC mission, which was to review and evaluate the science, not to
provide practice guidelines or recommendations. Second, Committee members were
concerned that the criteria used to evaluate evidence for the safe and
effective use of medical interventions or therapies (such as drugs or medical
devices) developed to treat disease are not readily applicable for evaluating
the effects of lifestyle changes on chronic disease prevention, where standards
of experimental design such as double blinding are exceptionally difficult, if
not impossible.
The Committee also recognized that because of logistical, cost, and
ethical issues, few RCTs have been conducted to link physical activity to
reduced rates of chronic diseases. This situation is not very different from
that linking other health-related behaviors to the prevention of clinical
outcomes. A good example is cigarette smoking. For obvious ethical reasons, no
one has conducted an RCT of the impact of starting cigarette smoking on health
outcomes, such as lung cancer, chronic obstructive pulmonary disease, or
coronary heart disease. A similar situation exists for the relation between
saturated fat or trans-fatty acid intake and the prevention of coronary heart
disease. Yet, the weight of evidence is believed to be so strong from
observational studies that urging the public to stop smoking or reduce their
intake of saturated fat or trans-fatty acids are major components of national
public health campaigns. Similarly, data linking physical activity to lower
rates of all-cause mortality, coronary heart disease, stroke, and type 2
diabetes based on observational studies are strong and, further, are supported
by RCTs showing significant favorable effects on key biomarkers for these
conditions. The result of these deliberations by the PAGAC was the development
of the evidence rating criteria presented in Table
Selected PAGAC members were then asked to integrate the main
conclusions from these subcommittee summaries under the headings of youth,
adults, older adults, understudied populations, and adverse events. These
summary conclusions were presented to PAGAC members, and each set of
conclusions was discussed and edited. A final set of conclusions was developed
using a consensus process.
Following the PAGAC meeting on February 28-29, 2008, the Committee
prepared the following information, which summarizes the major conclusions of
each committee. The sum of the evidence provided here for a wide range of
health and fitness outcomes strongly supports the value of being physically
active versus being sedentary throughout the lifespan.
Types of studies?
Type 3a – extensive
What is the nature of the association of physical activity
(PA) with All-Cause Mortality?
There is a clear inverse relationship between PA and all-cause
Strength of evidence: Strong
What is the effect size?
There is about a 30% risk reduction across all studies, comparing
most with least active subjects.
Is there any evidence for an effect of sex, age, or
There is evidence that this association exists for both men and
women, as well as for people both younger than age 65 years or 65 years of age
and older. There is also evidence that this association exists for different
race/ethnic groups.
Strength of evidence: Sex = Strong, <65 & 65+ years =
Strong, Race/Ethnicity = Reasonable
Is there a dose-response effect?
There is an inverse dose-response relation for total volume of PA
(i.e., total energy expenditure). The shape of the dose-response curve appears
curvilinear in that larger risk decreases are seen at the lower end of the
physical activity spectrum than at the upper end. There are limited data on an
inverse dose-response relation for intensity, which is independent of its
contribution to the total volume of PA (i.e., limited data suggest that
vigorous physical activity may be associated with further risk reduction
compared with moderate-intensity activity when the total volume of energy
expenditure is the same).
Strength of evidence: Volume = Strong, Intensity =
What is an effective PA dose regarding mode, duration,
intensity, and frequency that is supported by the evidence? (Strength
of evidence in parentheses)
Data indicate at least 2 to 2.5 hours per week of
moderate-to-vigorous physical activity are needed to see significantly lower
risk (Strong).
Data are primarily for aerobic leisure-time physical activity
(LTPA) (Strong).
There are also specific data showing that walking at least 2 hours
per week is associated with significantly lower risk (Strong).
Some evidence also indicates that all activities count
This amount — 2 to 2.5 hours per week of
moderate-to-vigorous PA — does not represent a threshold level for risk
reduction. The data consistently support a "some is good; more is better"
message (Strong). Some data indicate that among populations where physical
activity levels are likely to be low (e.g., middle-aged and older women; older
men), significantly lower mortality rates are observed at levels less than 2 to
2.5 hours per week of moderate-to-vigorous PA (Limited).
What is the evidence on accumulation? (Strength
of evidence in parentheses)
No direct data on multiple short bouts versus one long bout.
However, indirect data come from epidemiologic studies showing an
inverse association with total volume, where the PA is likely to be accumulated
from activities of different (but unknown) durations (Reasonable).
What other unique comments should be made about the
evidence of PA with this health outcome? (Strength of evidence in
The association of PA and all-cause mortality is independent of
body mass index (Strong); this association is seen regardless of whether
persons are normal weight, overweight, or obese (Reasonable).
Type 3a – extensive for coronary heart disease (CHD),
cardiovascular disease (CVD), and stroke
Type 1 – extensive for hypertension, atherogenic
dyslipidemia, and cardiorespiratory fitness
What is the nature of the association of PA with
Cardiorespiratory Health?
There is a clear inverse relation between PA and cardiorespiratory
health (CHD, CVD, stroke, hypertension, and atherogenic dyslipidemia).
The data imply relations with physical activity volume, with less
information about intensity and none for frequency and duration per session for
CVD clinical events.
Physical activity improves cardiorespiratory fitness. Fitness has
direct dose-response relations between intensity, frequency, duration, and
volume. There is limited evidence for an accumulation effect.
There is a 20% to 35% lower risk for CVD, CHD, and stroke.
Participation in aerobic activity improves cardiorespiratory
fitness in a dose-response fashion according to the frequency, duration,
intensity, and total volume of the exposure. Percentage increases are highly
dependent on fitness levels at baseline, sex, and age of the study population,
and range from 4.5% with low-volume brisk walking to close to 20% with
high-volume, high-intensity exercise training.
Is there any evidence for an effect of sex, age,
These associations exist for both men and women and individuals of
all ages. There is no evidence for sex-specific, age-specific, or race/ethnic
specific effects when volume is the exposure rather than relative
Strength of evidence: Sex = Strong, Age = Strong, Race/Ethnicity =
There is a dose-response relation for CVD and CHD. There appears
to be an L-shaped relation for stroke. The relations are all most closely
related to volume, with less information about intensity and none for frequency
and duration of sessions. Minutes per week is a less powerful parameter of dose
response than is volume per week (kilocalories per week; MET-minutes per
Physical activity improves cardiorespiratory fitness. For fitness
there are direct dose-response relations between intensity, frequency,
duration, and volume. There is mixed evidence for an accumulation effect.
What is an effective physical activity dose regarding
mode, duration, intensity, and frequency that is supported by the evidence?
(Strength of evidence in parentheses)
At least 800 MET-minutes per week or 12 miles per week (moderate
and/or vigorous); includes specific data on brisk walking at least 2 hours per
week (Strong). Data are primarily for aerobic LTPA (Strong) on top of usual
activities of daily living. Risk reductions start to be seen at levels below
800 MET-minutes per week or 12 miles week (Reasonable).
What is the evidence on accumulation?
Very limited and mixed data available and mostly for
cardiorespiratory fitness. Sparse evidence for other CRH outcomes.
Strength of evidence: Limited
What other unique comments should be made about the
evidence of PA with this health outcome?
Notable lack of evidence for frequency, duration, and intensity
effects on hard cardiorespiratory health outcomes (CVD, CHD, and stroke) and
lack of trial evidence for duration and intensity for cardiovascular risk
factors (hypertension and atherogenic dyslipidemia).
Type 2a (small body) and 3a (reasonable body) for type 2
Type 3a/b (reasonable body) for metabolic syndrome
What is the nature of the association of PA with Metabolic
There is a clear inverse relationship between PA and metabolic
health, including the prevention of type 2 diabetes and metabolic syndrome.
There is a 30% to 40% lower risk for type 2 diabetes and metabolic
syndrome in at least moderately active people compared to sedentary
This association exists for both men and women, as well as for
older and younger persons. There is reasonable evidence to show the association
exists for different race/ethnic groups.
There is an inverse dose-response association between volume of PA
and the development of metabolic syndrome as well as the development of type 2
Strength of evidence: Reasonable
What is an effective PA dose regarding: mode, duration,
intensity, and frequency that is supported by the evidence? (Strength
of evidence in parentheses)
Data indicate at least 120 to 150 minutes per week of
moderate-to-vigorous PA is needed to see significantly lower risks (Strong).
Data are primarily for aerobic LTPA (Strong). Risk reductions start to be seen
at levels below the 120 to 150 minutes per week level of PA
There are limited data on accumulation.
There is limited evidence that PA helps to control HbA1c
There is very limited evidence that PA helps to prevent
gestational diabetes.
Weight maintenance (less than 3% change in body
Type 1, 2, 3a
Weight loss (at least 5% loss of body
Type 1
Weight maintenance following weight
Type 2
Abdominal obesity:
Type 1, 2
What is the nature of the association of PA with Energy
Balance? (Strength of evidence in parentheses)
Weight maintenance (less than 3% change in
There is a favorable and consistent effect of aerobic PA on
achieving weight maintenance (Strong). The evidence is less consistent for
resistance training, in part, because of the compensatory increase in lean mass
(Moderate), and the smaller volumes of exercise employed.
Weight loss (at least 5% loss of
The amount of weight lost due to PA (alone) is dependent on the
volume of activity, and few studies have used a volume of PA large enough to
achieve a 5% weight loss. If an isocaloric diet is maintained throughout the PA
intervention, weight loss is similar to what is observed for dietary
interventions and clearly exceeds 5% (Strong).
PA promotes less weight regain after a period of significant
weight loss (Moderate).
A decrease in total abdominal adiposity and intra-abdominal
adiposity is associated with aerobic PA (Moderate to Strong). The effect is
less well described for resistance training (Weak).
What is the effect size? (Strength of evidence in
Aerobic PA has a consistent effect on achieving weight maintenance
(Strong); resistance training has a moderate effect (Limited).
PA alone has no effect on achieving a 5% weight loss, except at
very large volumes of PA or when an isocaloric diet is maintained throughout
the PA intervention (Strong).
Aerobic PA has a reasonably consistent effect on weight
maintenance following weight loss (Moderate).
Aerobic PA has a consistent effect on total abdominal adiposity
and a smaller effect on intra-abdominal adiposity (Strong). Resistance training
has a small and less consistent effect on total abdominal and intra-abdominal
adiposity (Limited).
There is some evidence that the amount of physical activity needed
to maintain a constant weight differs between men and women and increases with
age. However, the evidence is not sufficient to recommend differential physical
activity regimens based on sex or on age alone.
The paucity of literature, particularly of the stronger
longitudinal cohort or randomized controlled intervention study designs, makes
it unwise to draw conclusions as to whether the physical activity
recommendation should differ by racial/ethnic or socioeconomic status
Strength of evidence: Sex = Weak, Age = Weak, Race/Ethnicity =
Is there a dose-response effect? (Strength of
evidence in parentheses)
There is no evidence for a dose-response effect for PA and weight
maintenance, as it has not been specifically tested.
Weight loss:
There is a clear, consistent dose-response effect of aerobic PA on
weight loss (Strong).
A dose-response is present — those performing the larger
volumes of aerobic PA had less weight regain (Moderate).
Larger, well-designed studies report a dose-response relationship
for aerobic PA related to abdominal obesity measures (Moderate).
Weight maintenance (less than 3%):
The optimal amount of physical activity needed for weight
maintenance over the long-term is unclear. However, there is clear evidence
that physical activity provides benefit for weight stability. There is a great
deal of inter-individual variability with physical activity and weight
stability, and many persons may need more than 150 minutes of
moderate-intensity activity per week to maintain weight. Data from recent
well-designed RCTs lasting up to 12 months indicate that aerobic physical
activity performed to achieve a volume of 13 to 26 MET-hours per week is
associated with approximately a 1% to 3% weight loss, which is generally
considered to represent weight stability. Thirteen MET-hours per week is
approximately equivalent to walking at 4 miles per hour for 150 minutes per
week or jogging at 6 miles per hour for 75 minutes per week.
Weight loss (at least 5% weight
There are clear, consistent data that a large volume of physical
activity is needed for weight loss in the absence of concurrent dietary
changes. Physical activity equivalent to 26 kilocalories per kilogram (1,560
MET-minutes) or more per week is needed for weight loss of 5% or greater
(Moderate); less amounts of weight loss are seen with smaller amounts of
physical activity. This relatively high volume of physical activity is
equivalent to walking about 45 minutes per day at 4 miles per hour or about 70
minutes per day at 3 miles per hour, or jogging 22 minutes per day at 6 miles
per hour.
Weight maintenance following weight loss:
PA equivalent to 30 kilocalories per kilogram per week or more.
This is equivalent to walking about 50 minutes per day at about 4 miles per
hour or 80 minutes per day at about 3 miles per hour, or jogging for 25 minutes
per day at 6 miles per hour (Moderate).
Aerobic physical activity in the range of 13 to 26 kilocalories
per kilogram per week results in decreases in total and abdominal adiposity
that are consistent with improved metabolic function. Thirteen MET-hours per
week is approximately equivalent to walking at 4 miles per hour for 150 minutes
per week or jogging at 6 miles per hour for 75 minutes per week. However,
larger volumes of physical activity (e.g., 42 kilocalories per kilogram per
week) result in decreases in intra-abdominal adipose tissue that are 3 to 4
times that seen with 13 to 26 kilocalories per kilogram per week of physical
Weight maintenance (less than 3%):
Accumulation of energy expenditure due to PA is what is important
to achieving energy balance* (Strong). Accumulation of PA can be obtained in
short multiple bouts or one long bout to meet PA expenditure goals for weight
maintenance (Moderate).
There is evidence that accumulation of PA independent of
distribution of PA bouts is what is important for weight loss (Limited);
however, it is difficult accumulate large volumes of PA without concentrated
There is reasonable evidence that accumulation of PA independent
of distribution of bouts is what is important for weight stability following
weight loss (Limited); however, it is difficult accumulate large volumes of PA
without concentrated bouts.
This has not been tested.
*NOTE: It is important to note that the role of energy intake
(diet) must be considered in any discussion of physical activity and weight
control. Weight loss in excess of 5% can be achieved with large volumes of
physical activity. However, a more predictable weight loss occurs when energy
intake is held constant during a physical activity intervention.
Type 3a: fractures
Type 1, 2a: bone density
Type 3a: prevention and/or promotion of osteoarthritis (OA)
Type 1: improvement of OA, rheumatoid arthritis (RA), and
Type 1: muscle strength
What is the nature of the association of PA with
Musculoskeletal Health? (Strength of evidence in parentheses)
There is an inverse association of PA with relative risk of hip
fracture (Moderate) and vertebral fracture (Weak). Increases in exercise
training can increase, or minimize the decrease, in spine and hip bone mineral
density (BMD) (Moderate).
In the absence of a major joint injury, there is no evidence that
regular moderate PA promotes the development of OA (Moderate). Participation in
low/moderate levels of PA may provide a mild degree of protection against the
development of OA (Weak, Limited). Participation in moderate-intensity,
low-impact PA has disease-specific benefits (pain, function, quality of life,
and mental health) for people with OA, RA, and fibromyalgia (Strong). PA may
delay the onset of disability in people with OA (Weak).
Increases in exercise training enhance skeletal muscle mass,
strength, power, and intrinsic neuromuscular activation (Strong).
Risk reduction of hip fracture is 36% to 68% at the highest level
of PA (Moderate). The magnitude of effect of PA on BMD is 1% to 2%
Risk reduction of incident OA for various measures of walking
ranges from 22% to 83% (Weak). Among adults with osteoarthritis, pooled effect
sizes (ES) for pain relief are small to moderate (ES = 0.25 to 0.52); for
function and disability ES are small (function ES = 0.14 to 0.49, disability ES
= 0.32 to 0.46) (Strong).
The magnitude of the effect of resistance types of PA on muscle
mass and function is highly variable and dose-dependent (Strong).
Is there any evidence for an effect of sex, age,
race/ethnicity? (Strength of evidence in parentheses)
There is evidence for a lower relative risk of hip fracture in
older women and men; the evidence is more consistent in women (Moderate).
Benefits of PA on BMD have been found to occur in premenopausal women,
postmenopausal women, and adult men; the evidence is more consistent in women
(Moderate). Information on race and ethnic specificity is lacking.
Female sex and older age are established risk factors for incident
OA (Strong), the evidence for race/ethnicity is equivocal (Weak). Male and
female adults of any age with OA benefit from both aerobic and resistance
exercise (Strong). Women may have a bigger benefit from resistance exercise,
likely due to lower baseline muscular strength (Limited).
Benefits are similar in men and women and pervasive across the
life span (Strong), although the magnitude of the benefits may be attenuated in
old age (Moderate). Information on race and ethnic specificity is lacking.
There is evidence of a dose-response association of PA with hip
fracture risk (Moderate). Dose-response effects have not been adequately tested
for PA and BMD.
High-level (elite, professional) athletes competing in high
joint-loading sports (e.g., football, soccer, track and field) may have an
increased risk of hip/knee OA (Strong). Dose-response effects have not been
tested with regard to PA among adults with arthritis.
There is a dose-response with greatest gains in muscle mass and
muscle strength experienced with higher-intensity protocols (Strong).
PA of 4 or more hours per week of walking, 2 to 4 hours per week
of LTPA, 9 to 14.9 MET hours per week of PA, and and1 hour per week of PA have
been associated with a 36% to 41% lower risk in hip fracture risk.
Weight-bearing endurance and resistance types of PA (i.e., exercise training)
are effective in promoting increases in BMD (moderate-to-vigorous intensity; 3
to 5 days per week; 30 to 60 minutes per session). Walking-only protocols found
a benefit on spine BMD (Moderate).
For adults with arthritis, benefits in pain, function, and
disability were noted with programs averaging a total volume of 130 to 150
minutes per week: 30 to 60 minutes per session; 3 to 5 days per week; moderate
intensity; low-impact (Strong). Both aerobic and muscle strengthening
activities improve joint function and reduce pain.
Progressive, high-intensity (60% to 80% of 1 repetition maximum
[1RM]) muscle-strengthening activities can preserve or increase skeletal muscle
mass, strength, power, and intrinsic neuromuscular activation (Strong).
The effects of accumulation have not been tested in humans.
One study of fibromyalgia patients supports equal benefits
(improved function, well-being, disease activity) for 2 15-minute sessions per
day and 1 30-minute session per day of moderate-intensity, low-impact aerobic
exercise (Limited).
The effects of accumulation have not been tested in
Individual RCTs support basic science findings that intensity of
loading forces is a key determinant of the skeletal response. Studies of
laboratory animals also suggest that multiple, short bouts of PA should have
more favorable effects on bone than a single, longer bout of PA.
Joint injuries and excess body mass are more important risk
factors for incident OA than sports/PA participation (Consistent, Strong).
Endurance types of PA do not increase muscle mass, but may
attenuate the rate of loss with aging and preserve function (Moderate).
Functional Health:
Type 3a, Type 1
What is the nature of the association of PA with
Functional Health? (Strength of evidence in parentheses)
There is observational evidence that mid-life and older adults who
participate in regular PA have reduced risk of moderate/severe functional
limitations and role limitations (Moderate to Strong). In older adults with
existing functional limitations, there is fairly consistent evidence that
regular PA is safe and has a beneficial effect on functional ability
(Moderate); however, there is currently little or no experimental evidence in
older adults with functional limitations that PA maintains role ability or
prevents disability.
In older adults at risk for falls, there is consistent evidence
that regular PA is safe and reduces risk of falls (Strong).
There is about a 30% risk reduction for the prevention or delay in
function and/or role limitations with PA (Moderate to Strong).
It is difficult to ascertain an effect size for the
maintenance/improvements in functional ability due to the variety of outcomes
Older adults who participate in regular PA have about a 30% lower
risk of falls (Strong).
The association exists for both men and women with respect to
preventing and maintaining or improving functional health and reducing risk of
falls (Strong). The association exists for preventing functional limitations in
middle-aged and older adults (Strong); the association for maintaining or
improving functional heath is seen in older adults aged 65 years and older
(Moderate); the association with falls reduction is seen in older adults at
increased risk for falls (Strong). There is limited evidence to show an
association exists for different race/ethnic groups for all outcomes
There appears to be a dose-response effect for PA in preventing or
delaying function and/or role limitations, with greatest risk reduction seen
with the highest levels of PA (Moderate). It is unclear whether there is a
dose-response effect for PA in maintaining or improving functional ability, as
this has not been tested.
It is unclear whether there is a dose-response effect for PA in
the reduction of falls in older adults, as this has not been tested.
The most evidence of a dose response exists for walking activities
(Strong); it is not possible at this point to ascertain dose of PA due to the
nature of the study designs.
Evidence exists for exercise programs that include periods of 30
to 90 minutes of moderate-to-vigorous PA, 3 to 5 days per week, in which most
of this time is devoted to aerobic and muscle-strengthening activities (with a
smaller amount of time spent on other forms of activity, such as flexibility)
(Moderate). When it was possible to determine the amount of time spent just on
aerobic activity, studies usually varied from 60 minutes per week to 150
minutes per week (Moderate).
Evidence exists for exercise programs that include 3 times per
week of balance and moderate-intensity strengthening activities at 30 minutes
per session, with additional encouragement to participate in moderate-intensity
walking activities 2 or more times per week for 30 minutes a session
Evidence also exists for tai chi exercises (Moderate). It was
difficult to ascertain an optimal PA pattern for tai chi. Tai chi studies
ranged from 1 hour per week to 3 hours or more per week (Limited).
What is the evidence around accumulation?
No evidence is available.
Relative intensity is important to consider, as fitness levels are
very low in many older adults.
It is important to increase exercise intensity and volume slowly
to reduce adverse events, especially injuries.
What is the nature of the association of PA with
There is a clear inverse association between PA and prevention of
breast and colon cancer.
There is about a 30% lower risk for colon cancer and about a 20%
lower risk for breast cancer.
This association exists for both men and women for colon cancer,
as well as for adults of different ages. There is reasonable evidence to show
an association exists for different race/ethnic groups.
There is a dose-response association between PA and the
development of breast/colon cancer, but the shape of the curve is unclear.
Data indicate at least 30 to 60 minutes per day of
moderate-to-vigorous PA is needed to see significantly lower risks
(Reasonable). Data are primarily for aerobic LTPA (Strong).
There is no information on accumulation of PA and cancer. However,
the LTPA carried out by subjects in observational studies likely is accumulated
from different activities of various, but unknown, duration (Limited).
There is a small body of Type 1 evidence for an association
between improved quality of life and fitness in breast cancer survivors
There is growing evidence of a reduced risk of cancers of the
endometrium and lung with increased physical activity (Reasonable).
Type 1, 2a, 3a and 3b
What is the nature of the association of PA with Mental
There is clear evidence that PA reduces risk of depression and
cognitive decline in adults and older adults. There is some evidence that PA
improves sleep. There is limited evidence that PA reduces distress/well-being
and anxiety.
Strength of evidence: Depression and cognitive health = Strong;
Sleep = Moderate; Distress/well-being and Anxiety = Limited
There is about a 20% to 30% lower risk for depression,
distress/well-being, and dementia.
Risk reduction has been observed for men and women of all ages,
but few studies have directly compared results according to sex or age.
Racial/ethnic minority groups have been underrepresented in most studies, but
limited results from prospective cohort studies suggest that risk reduction
among blacks and Hispanic/Latinos is similar to that among whites.
Reasonable evidence indicates a dose-response effect between PA
and mental health. Moderate and high levels of physical activity are similarly
associated with lower risk of depression and distress/well-being, compared to
low levels of physical activity exposure, which is nonetheless more protective
than inactivity or very low levels of physical activity (Moderate). There is
insufficient evidence to determine whether there are dose-response relations
with physical activity for anxiety, cognitive health, and sleep
What is an effective PA dose regarding mode, duration,
intensity, and frequency that is supported by the evidence?
Most evidence comes from PA programs of 3 to 5 days per week, 30
to 60 minutes per session and moderate to vigorous intensity. Most evidence
comes from aerobic and multi-modal interventions (usually aerobic plus muscle
strengthening activities). Only a few studies have manipulated and compared
features of physical activity and their effects on mental health. Aerobic or
resistance, and their combination, have positive effects. However, the minimal
or optimal type or amount of exercise for mental health is not yet known
Strength of evidence: Limited to Moderate
Mental health outcomes have not differed when physical activity
was continuous or intermittent in nature, but studies have not directly
compared single versus multiple sessions of similar amounts of physical
activity in controlled studies. Hence, there is insufficient evidence to
determine whether physical activity can be accumulated to achieve mental health
Positive findings from initial studies suggest that physical
activity and exercise might reduce the onset, progression, or adverse impact of
central nervous system disorders other than dementia that contribute to
disability and mortality risk, such as multiple sclerosis and Parkinson's
disease. Benefits of physical activity may also extend to other aspects of
mental health that are important contributors to overall quality of life, such
as self-esteem and feelings of energy/fatigue. Sufficient evidence exists to
encourage more study in these areas, but presently not enough studies are
available to draw conclusions about how the effects of physical activity or
exercise may differ according to types of people or types and amounts of
physical activity.
Physical Fitness:
Type 1, 2a, 2b, 3a, 3b: Cardiorespiratory
Type 2b: Muscular Strength
Body Mass and Composition:
Type 1, 2b, 3a, 3b
Cardiovascular and Metabolic Health:
Bone Health:
Type 1, 3a
Mental Health:
Type 1, 2b, 3a, 3b: Depression
Type 1, 3b: Anxiety
What is the nature of the association of PA with health
for Youth? (Strength of evidence in parentheses)
There is a clear, positive association between PA and
cardiorespiratory fitness and muscular strength (Strong).
Body Composition:
There is a clear, positive association between PA and favorable
body composition (Strong).
There is a clear, positive association between PA and
cardiovascular and metabolic health (Strong).
There is a clear, positive association between PA and bone health
There appears to be an association between PA and reduced symptoms
of depression (Moderate), anxiety (Weak), and higher self esteem
There appears to be a dose-response relationship; however, the
precise pattern of this relationship has not been determined.
Other Outcomes:
Either evidence is insufficient or the varying methodologies and
insufficient numbers of intervention trials preclude inferences about
dose-response patterns for the remainder of the outcomes. Dose-response studies
are needed.
The association between PA and cardiorespiratory fitness and
muscle strength exists for both boys and girls, as well as in children and
adolescents (Strong). The research is not adequate to draw conclusions about
The research is not adequate to draw conclusions about age,
biological maturity, and race/ethnicity for body mass and composition.
Very little is known about the effects of sex, age, biological
maturity, and race/ethnicity on the relationship of PA to cardiovascular and
metabolic health.
This association exists for both boys and girls, and is influenced
by age and developmental status (Strong). The window of opportunity appears to
be in puberty and pre-menarchal years (Moderate). The research is not adequate
to draw conclusions about race/ethnicity.
Mental Health:
The research is not adequate to draw conclusions about sex, age,
maturity, and race/ethnicity on the relationship of PA to mental
Overall Conclusion:
Important health and fitness benefits can be expected by most
children and youth who participate daily in 60 or more minutes of
moderate-to-vigorous physical activity (Strong).
Vigorous aerobic activity 3 or more days per week significantly
improves cardiorespiratory fitness. Resistance training 2 or 3 days per week
significantly improves muscular strength.
Reductions in overall adiposity and visceral adiposity with
exposure to regular moderate-to-vigorous PA 3 to 5 days per week for 30 to 60
minutes have been observed.
Cardiovascular and Metabolic Health:
Vigorous aerobic activity 3 or more days per week significantly
improves cardiovascular and metabolic health.
Targeted weight-loading activities that simultaneously influence
muscular strength, done 3 or more days per week, significantly improve bone
mineral content and density.
Overall Conclusions:
It is important to minimize the potential risks of overtraining
and injuries.
A wide-range of developmentally appropriate activities for
children should be chosen.
Type 1, 2a, 2b
What is the nature of the association of PA with health
for people with disabilities?
Consistency of evidence supports the use of PA to improve key
health outcomes in people with physical and cognitive disabilities.
Strength of evidence:
Physical Disability:
The strongest evidence is found under the categories of
cardiorespiratory, musculoskeletal, and mental health.
Cognitive Disability:
The strongest evidence is found under the categories of functional
health and mental health.
What is the effect size? N/A
Level of evidence was based on number of significant trials
reporting positive outcomes. Definition of strength of evidence:
Strong: At least 75% of reviewed trials
Moderate: 50% to 74% of reviewed trials
Limited: Up to 49% of reviewed trials
Physical Disability:
Strong for cardiorespiratory health, musculoskeletal health, and
mental health; Moderate for functional health.
Cognitive Disability:
Strong for functional health and mental health; Moderate for
cardiorespiratory health, musculoskeletal health, and healthy weight and
metabolic health.
No direct data on dose response are available.
The majority of the studies included exercise doses typically used
in studies with the general population:
Intensity: 50% or more of heart rate reserve or VO2peak
Frequency: 3 to 5 days per week (Strong)
Duration: 30 to 60 minutes (Strong)
No direct data are available on multiple bouts versus one long
What other unique comments should be made about the
evidence of PA for people with disabilities?
PA is relatively safe and effective for people with disabilities
and can improve several key health outcomes. Very few serious adverse events
have been reported (1.15% exercise versus 0.60% for controls).
Types: 1, 3a, 4
What is the nature of the association of PA with Adverse
Events? (Strength of evidence in parentheses)
The risk of musculoskeletal injuries is lower for non-contact
(e.g., walking) and limited contact (e.g., baseball) activities than for
contact (e.g., basketball) and collision (e.g., football) activities
The usual dose of regular physical activity is directly related to
the risk of musculoskeletal injury (Strong) and inversely related to the risk
of sudden adverse cardiac events (Strong).
The risk of musculoskeletal injuries and sudden cardiac adverse
events is directly related to the size of the difference between the usual dose
of activity and the new or momentary dose of activity (Strong).
The most consistently reported risk factor for musculoskeletal
injuries (Strong) and sudden cardiac adverse events (Strong) is inactivity and
low fitness.
Older people are more susceptible to activity-related
musculoskeletal injuries (Weak).
Females are more likely than males to suffer musculoskeletal
injuries, but the difference appears to be due to lower fitness (Weak).
Differences in the risk of musculoskeletal injuries among
different race/ethnicity groups do not appear to be marked but have been
infrequently studied (Weak).
A series of small increases in activity each followed by a period
of adaptation will cause fewer adverse events than will larger or more frequent
increases in activity (Weak).
The incidence of adverse events caused by moderate-intensity
physical activity appears to be low (Weak).
What other unique comments should be made about the
evidence of PA and Adverse Events?
The benefits of regular physical activity far outweigh the risks
of adverse events for outcomes that encompass a broad spectrum of medical
maladies such as all-cause mortality (Strong), functional health (Moderate),
and medical expenditures (Strong).
Appropriate clothing, gear, and equipment, as well as a safe
environment, reduce the risk of adverse events.
After it summarized the evidence linking physical activity to a variety
of health outcomes and populations, the PAGAC's next step was to integrate this
evidence in the following questions and responses. Because the primary charge
to the PAGAC was to review the scientific evidence to inform the development of
public health physical activity guidelines and policy for Americans, the
questions and answers primarily focus on major outcomes and on issues involving
dose response, particularly the minimum amount, intensity, duration, and
frequency associated with health benefits, as well as whether additional health
benefits are observed at higher levels of physical activity.
Does existing evidence indicate that people who are habitually
physically active have better health and a lower risk of developing a variety
of chronic diseases than do inactive people?
Yes. Very strong scientific evidence based on a wide range of
well-conducted studies shows that physically active people have higher levels
of health-related fitness and a lower risk profile for developing a number of
disabling medical conditions than do people who are inactive. In
children and youth major benefits supported by strong evidence
include enhanced cardiorespiratory and muscular fitness, cardiovascular and
metabolic health biomarkers, bone health, body mass and composition. Less
strong evidence supports selected measures of mental health. In adults
and older adults strong evidence demonstrates that, compared to less
active counterparts, more active men and women have lower rates of all-cause
mortality, coronary heart disease, high blood pressure, stroke, type 2
diabetes, metabolic syndrome, colon cancer, breast cancer, and depression.
Strong evidence also supports the conclusion that, compared to less active
people, physically active adults and older adults exhibit a higher level of
cardiorespiratory and muscular fitness, have a healthier body mass and
composition, and a biomarker profile that is more favorable for the preventing
cardiovascular disease and type 2 diabetes and enhancing bone health. Modest
evidence indicates that physically active adults and older adults have better
quality sleep and health-related quality of life. For older
adults, strong evidence indicates that being physically active is
associated with higher levels of functional health, a lower risk of falling,
and better cognitive function.
Time course for benefits. Strong
evidence indicates that increases in cardiorespiratory and muscular fitness and
improvements in various biomarkers that appear in the causal pathways between
increased activity and favorable clinical outcomes and in some clinical
outcomes, such as a decrease in depression, frequently occur in weeks or a few
months in response to a sustained increase in moderate- to vigorous-intensity
activity. The time course for a decrease in occurrence of various chronic
disease clinical outcomes has not been established but appears to require
longer exposure to an increased level of activity.
What does the evidence indicate about dose of physical
activity that is most likely to provide many of the benefits indicated in
Current science, inter-individual differences in the biological
responses to specific activity regimens and the wide variety of benefits
provided by being physically active do not allow a single, highly precise
answer to this question. However, as a starting place for overall public health
benefit, data from a large number of studies evaluating a wide variety of
benefits in diverse populations generally support 30 to 60 minutes per day of
moderate- to vigorous-intensity physical activity on 5 or more days of the
week. For a number of benefits, such as lower risk for all-cause mortality,
coronary heart disease, stroke, hypertension, and type 2 diabetes in adults and
older adults, lower risk is consistently observed at 2.5 hours per week
(equivalent to 30 minutes per day, 5 days per week) of moderate- to
vigorous-intensity activity. The amount of moderate- to vigorous-intensity
activity most consistently associated with significantly lower rates of colon
and breast cancer and the prevention of unhealthy weight gain or significant
weight loss by physical activity alone is in the range of 3 to 5 hours per
By converting the intensity and duration of various aerobic
activities into MET-minutes or MET-hours (intensity in METs x duration), it is
possible to combine activities of different types and intensities into a single
measure of amount of activity. For many studies, the amount of moderate- and
vigorous-intensity activity associated with significantly lower rates of
disease or improvements in biomarkers and fitness is in the range of 500 to
1,000 MET-minutes per week. An adult can achieve a target of 500 MET-minutes
per week by walking at about 3.0 miles per hour for approximately 150 minutes
per week (7.5 miles), walking faster at 4.0 miles per hour for 100 minutes (6.6
miles) or jogging or running at 6 miles per hour for about 50 minutes per week
(5.0 miles). To achieve 1,000 MET-minutes per week, these amounts of activity
would need to be doubled. These MET-minutes per week targets also can be
achieved by performing various combinations of activities of different
intensities and durations (See Table
D.3 in Part D:
Background and its accompanying text for more details).
Very limited data are available on dose response in children and
youth, but strong evidence indicates that better fitness and health outcomes
are observed when 60 minutes of moderate- to vigorous-intensities activity of
various types is accumulated throughout the day.
Is there evidence that performing more than 30 minutes per day
of moderate- to vigorous-intensity activity on most days confers greater health
benefits for some health outcomes?
Yes. For a variety of health and fitness outcomes, including
chronic disease prevention, improvement of various disease biomarkers and the
maintenance of a healthy weight, reasonably strong evidence demonstrates that
amounts of moderate- to vigorous-intensity activity that exceed 150 minutes per
week are associated with greater health benefits. However, in a number of
studies where such a dose response is observed in preventing chronic disease or
reducting all-cause mortality, the relation appears to be curvilinear. This
means that the absolute increase in benefits becomes less and less for any
given increase in the amount of physical activity. An example of a curvilinear
dose-response relation between the relative risk of all-cause mortality and the
amount of moderate-to-vigorous physical activity in hours per week is displayed
in Figure G1.3 (Part G. Section 1:
All-Cause Mortality). As stated in that chapter, "On average,
compared to less than 0.5 hours per week of moderate-to-vigorous physical
activity, engaging in approximately 1.5 hours per week in such activity is
associated with about a 20% reduction in risk of all-cause mortality during
follow-up. Additional amounts of physical activity are associated with
additional reductions, but at smaller magnitudes, such that approximately 5.5
hours per week is required to observe a further 20% reduction in risk (i.e.,
approximately 7.0 hours per week is associated with approximately 40% reduction
in risk compared with less than 0.5 hours per week)." A somewhat similar
curvilinear relation appears to exist between amounts of moderate to vigorous
activity and risk of coronary heart disease. The added value of higher amounts
of activity for helping maintain a healthy body weight is discussed in the
responses to Questions 15 to 17.
For people who are physically inactive or unfit, does current
science support the concept that some activity is better than none?
PAGAC members spent substantial time considering this question and
concluded that for otherwise healthy sedentary individuals, some physical
activity is better than none. The least active in the population generally have
the highest risk for various negative health consequences and the most to gain
from becoming more active. Increasing evidence suggests that performing
activity in amounts of no more than about 1 hour per week at an intensity that
is moderate relative to the person's capacity will provide small increases in
cardiorespiratory and muscular fitness. In some studies, this amount of
activity is associated with lower risk of all-cause mortality and the incidence
of coronary heart disease. At this lower amount and intensity of activity, the
benefits usually are less than that observed with greater amounts of activity,
and studies are much less consistent about the nature and magnitude of these
benefits. Nevertheless, the dose-response curves for the major health benefits
clearly indicate an inverse relation between the dose of activity and rate of
disease. Although the minimum amount of activity needed to produce a benefit
cannot be stated with certainty, nothing would suggest a threshold below which
there are no benefits. Therefore, for inactive adults any increase appears
better than none. To achieve benefits for various health outcomes equivalent to
those achieved by their more active peers, very inactive adults will need to
progress gradually to higher amounts and intensities of activity.
If physical activity is performed at a vigorous intensity, are
the health outcomes greater than what has been observed with moderate-intensity
Yes. For some favorable health and fitness outcomes strong
evidence indicates that an increase in intensity is associated with greater
improvements compared to those observed with moderate-intensity activity. For
example, when a similar amount of activity is performed per session, such as
walking 3 miles per day, participants who walk faster have a greater increase
in cardiorespirtaory fitness than those who walk more slowly. One problem in
interpreting data that compares the benefits of moderate versus vigorous
activity in many observational and experimental studies is that along with a
difference in intensity between study groups, the amount or volume of activity
performed also differs. For example, if participants in two groups are
physically active 30 minutes per day 5 days per week, but one group walks at 3
miles per hour and the other jogs at 6 miles per hour, both the intensity and
the amount of activity performed will be different between the two groups. In
this case it is not possible to tell for sure whether differences in health or
fitness outcomes between the 2 groups are due to the difference in the
intensity or the amount of activity performed, or both. It is important to
recognize that the rate of energy expenditure goes up quite rapidly with
increases in intensity for some types of activity, such as going from walking
to jogging or running.
As people consider increasing their physical activity to high
doses of vigorous-intensity activity with the primary goal of achieving
favorable health outcomes, they need to be aware that such increases may
accelerate the injury rate disproportionate to the benefits accrued. This
appears to be especially true for people who have been inactive for extended
periods and who then rapidly increase the amount and/or intensity of activity
they perform.
Is there evidence that the frequency of physical activity
sessions influences health and fitness outcomes independent of the amount of
activity performed?
Very limited published research has systematically evaluated
health or fitness benefits in response to different frequencies of activity
sessions per week when the amount of activity is held reasonably constant. In
experimental studies, comparisons have been made between 2 versus 3 or more
sessions per week for both aerobic and resistance activity, but the amount of
activity performed increased as the number of sessions increased so it is not
possible to separate out the effects of increasing the session frequency from
the effects of increasing the amount. Most of the data from prospective cohort
studies with outcomes of all-cause mortality or chronic disease morbidity and
mortality do not provide information about frequency of activity independent of
intensity and amount, but the very limited data available indicate that when
activity amount is controlled for, the effect of session frequency is not
When many adults with sedentary occupations reach the range of 500
to 1,000 MET-minutes per week of leisure-time physical activity (LTPA), it is
very likely that this activity is the result of multiple sessions performed
during the week. Experimental studies that show significant improvements in
health-related outcomes typically feature session frequencies ranging between 3
and 5 times per week. Also, as the response to the Question 7 demonstrates, a
growing, but still limited, body of evidence indicates that multiple short
bouts (10 or more minutes) per day of aerobic activity produces improvements in
cardiorespiratory fitness and selected cardiovascular disease (CVD) biomarkers
similar to that obtained with a single bout of equal total duration and
Overall, one interpretation of the existing data is that for
health and fitness benefits, the frequency of activity is much less important
than the amount or intensity. Many experimental studies since 1995 have
demonstrated beneficial effects of 120 to 150 minutes per week of moderate- or
vigorous-intensity activity usually performed during 3 to 5 sessions per week,
so we know that this frequency of activity is effective. Only limited data are
available comparing the benefits from just one or two sessions per week with
multiple sessions spread throughout the week with activity amount and intensity
held constant. Again, while very limited data are available from direct
comparisons, the rate of certain types of adverse events (e.g., joint
irritation, muscle soreness) may be lower when performing a similar amount and
intensity of activity but during more sessions per week.
Is there evidence that physical activity can be accumulated
throughout the day for some health and fitness outcomes?
The concept of accumulation refers to performing multiple short
bouts of physical activity throughout the day. Some scientific evidence of
moderate strength suggests that accumulating 30 or more minutes per day of
moderate- to vigorous-intensity aerobic activity throughout the day in bouts of
10 minutes or longer produces improvements in cardiorespiratory fitness.
Limited data indicate that accumulated short bouts improve selected CVD
biomarkers in a manner generally similar to that observed when activity of a
similar amount and intensity is performed in a single bout of 30 or more
minutes. These experimental studies have primarily evaluated the effects of
multiple short bouts of 8 to 10 minutes duration versus longer bouts of
30 to 40 minutes and have not provided data on numerous shorter bouts
(e.g., 30 1‑minute bouts per day). Data on the effects of
accumulating activity involving multiple short bouts for the prevention of
major clinical outcomes, such as all-cause mortality, CVD, diabetes, and
selected cancers, are very limited because of the type of data collected from
questionnaires used in most prospective observational studies. Using data from
these questionnaires, it has not been possible to precisely differentiate
between activities conducted in a single, long bout versus those conducted in
multiple, short bouts over the day. Prospective cohort studies with clinical
outcomes have tended to present their data according to categories of the total
amount of activity performed, and this total amount is likely to be accumulated
from different activities of varying, but unknown durations and frequencies,
over the course of the day.
Is there evidence that performing bouts of walking as a
frequent routine is associated with positive health effects?
Yes. Strong evidence shows that a regimen of brisk walking
provides a number of health and fitness benefits for adults and older adults.
For example, women in the United States who walk 2 to 3 hours per week have a
significantly lower risk of all-cause mortality and cardiovascular disease than
do women who report no or very little walking. Also, for people walking for
equivalent amounts of time, a faster pace is associated with a lower risk of
cardiovascular disease, type 2 diabetes, and all-cause mortality. Strong
evidence also shows that frequent bouts of walking increase cardiorespiratory
fitness, especially in people who have been performing little activity on a
regular basis. Limited to moderate evidence suggests that walking helps to
maintain bone density and reduce fractures over time, especially in women, and
helps to maintain joint health and functional ability in adults and older
What does the scientific evidence indicate about the pattern
of physical activity that is most likely to produce the fewest adverse medical
events while providing health benefits?
Much of the research that addresses this question has evaluated
the risk of musculoskeletal injuries or sudden cardiac death during vigorous
physical activity (e.g., jogging, running, competitive sports, military
training) with few well-conducted studies evaluating the risk during
moderate-intensity activity intended primarily to improve health. Activities
with fewer and less forceful contact with other people or objects have
appreciably lower injury rates than do collision or contact sports. Walking for
exercise, gardening or yard work, bicycling or exercise cycling, dancing,
swimming, and golf, which are already popular in the United States, are
activities with the lowest injury rates. Risk of musculoskeletal injury during
activity increases with the total volume of activity (e.g., MET-hours per
week). Intensity, frequency, and duration of activity all contribute to the
risk of musculoskeletal injuries but their relative contributions are unknown.
For sudden cardiac adverse events, intensity appears to be more important than
frequency or duration. The limited data that do exist for medical risks during
moderate-intensity activity indicate that the risks are very low for activities
like walking and that the health benefits from such activity outweigh the
What does the scientific evidence say about actions that can
be taken to reduce the risk of injury during physical
Research with a variety of populations and methods indicates that
injuries are more likely when people are more physically active than usual. The
key point to remember, however, is that when individuals do more activity than
usual, the risk of injury is related to the size of the increase. A series of
small increments in physical activity each followed by a period of adaptation
is associated with lower rates of musculoskeletal injuries than is an abrupt
increase to the same final level. Although the safest method of increasing
one's physical activity has not been empirically established, adding a small
and comfortable amount of light to moderate-intensity activity such as walking,
5 to 15 minutes per session, 2 to 3 times per week, has a low risk of
musculoskeletal injury and no known risk of sudden severe cardiac events.
For people with stable activity habits, risk of injury is directly
related to the total volume of activity performed. Other things being equal,
people who are very physically active are more likely to incur an
activity-related injury than people who are active to a lesser degree. Some
evidence suggests, however, that even though more active people are more likely
to incur a physical activity-related injury they may suffer fewer overall
injuries because they are less likely to be injured in other settings such as
at work or around the home.
Is there evidence regarding who should see a physician or have
a medical examination before increasing the amount or intensity of physical
activity they perform?
The protective value of a medical consultation for persons with or
without chronic diseases who are interested in increasing their physical
activity level is not established. No evidence is available to indicate that
people who consult with their medical provider receive more benefits and suffer
fewer adverse events than people who do not. Also unknown is the extent to
which official recommendations to seek medical advice before augmenting one's
regular physical activity practices may reduce participation in regular
moderate physical activity by implying that being active may be less safe and
provide fewer benefits than being inactive.
What are the major health benefits provided by an increase in
aerobic (endurance) activity?
Aerobic activity of moderate to vigorous intensity performed on a
regular basis results in improvements in cardiorespiratory fitness
(VO2max) with an increase in the capacity and efficiency of the
cardiorespiratory system to transport oxygen to skeletal muscles and for
muscles to use this oxygen. This increase in cardiorespiratory fitness has a
strong inverse association with risk of all-cause mortality and a variety of
chronic diseases. The evidence is strong that aerobic activity has favorable
effects on various biomarkers for CVD and type 2 diabetes (e.g., atherogenic
lipoprotein profile, blood pressure, insulin sensitivity) in adults and older
adults with and without these diseases. Much of the physical activity
associated with lower risk for all-cause mortality, coronary heart disease,
stroke, hypertension, breast and colon cancer, and depression in many of the
prospective observational studies published since 1995 has been moderate- to
vigorous-intensity aerobic activity. For most people, performing aerobic
activity that requires the rhythmic use of large muscles and the movement of
the body mass against gravity (e.g., walking, jogging, cycling, climbing
stairs, dancing) is the most effective way to increase the rate of energy
expenditure and better achieve energy balance. For many of the benefits linked
to preventing various chronic diseases, aerobic activity performed at moderate
to vigorous intensity in the range of 500 to 1,000 MET-minutes per week is
associated with a significantly lower risk.
What are the major health benefits provided by resistance or
muscle-strengthening activity?
Strong evidence exists in youth, adults and older adults that
muscle-strengthening exercises that load skeletal muscle and bone increase
muscle mass, strength, and quality and increase bone mineral density. Evidence
is moderate that muscle-strengthening exercises improve functional ability in
older adults and lead to improvements in muscle strength, joint pain,
stiffness, and functional ability in adults with osteoarthritis. In combination
with balance training, muscle-strengthening exercises reduce risk of falls in
older adults at risk for falls (this evidence is discussed in more detail in
Question 22). Resistance exercise can help maintain lean body mass during a
program of weight loss, but by itself results in little weight loss.
Most of the evidence supports a resistance activity program with
the following characteristics: progressive muscle strengthening exercises that
target all major muscle groups performed on 2 or more days per week. To enhance
muscle strength, 8 to 12 repetitions of each exercise should be performed to
volitional fatigue. One set is effective; however, limited evidence suggests
that 2 or 3 sets may be more effective.
What is the evidence that flexibility activities provide
health benefits?
Flexibility is an important element of overall fitness. However,
the evidence that flexibility exercises by themselves confer health benefits is
very limited. Most well‑designed exercise interventions in youth, adults,
and older adults include a brief flexibility routine as part of the
intervention and often as the control condition, thus preventing the assessment
of the relative benefits of flexibility training alone. Some evidence indicates
that balanced exercise interventions that include flexibility activities reduce
the risk of injuries.
What is the amount of physical activity that is necessary for
weight stability over the long term?
The optimal amount of physical activity needed for weight
maintenance (defined as less than 3% change in weight) over the long-term is
unclear. However, the evidence is clear that physical activity provides benefit
for weight stability. A great deal of inter-individual variability exists with
physical activity and weight stability, and many persons may need more than 150
minutes of moderate-intensity activity per week to maintain weight. Data from
recent well-designed randomized controlled trials lasting up to 12 months
indicate that aerobic physical activity performed to achieve a volume of 13 to
26 MET-hours per week is associated with approximately a 1% to 3% weight loss
(i.e., an amount generally considered to represent weight stability). Thirteen
MET-hours per week is approximately equivalent to walking at 4 miles per hour
for 150 minutes per week or jogging at 6 miles per hour for 75 minutes per
What is the evidence for the amount of physical activity that
is necessary for weight loss in adults?
A wide range of studies provides evidence of a dose-response
relation between physical activity and weight loss. Clear, consistent data show
that a large volume of physical activity is needed for weight loss in the
absence of concurrent dietary changes. The physical activity equivalent of 26
kilocalories per kilogram of body weight (1,560 MET-minutes) or more per week
is needed for weight loss of 5% or greater. Smaller amounts of weight loss are
seen with smaller amounts of physical activity (as noted in R-15). This
relatively high volume of physical activity is equivalent to walking about 45
minutes per day at 4 miles per hour or about 70 minutes per day at 3 miles per
hour, or jogging 22 minutes per day at 6 miles per hour.
The role of energy intake (diet) must be considered in any
discussion of weight control. When calorie intake is carefully controlled at a
baseline level, the magnitude of any weight loss is what would be expected
given the increase in energy expenditure of the person's physical activity.
However, in situations in which people's dietary intake is not controlled, the
amount of weight loss due to the increase in physical activity is not
commensurate to what would be expected. Therefore, for most people to achieve
substantial weight loss (i.e., more than 5% decrease in body weight), a
dietary intervention also is needed. The dietary intervention could include
either maintenance of baseline caloric intake, or a reduction in caloric intake
to accompany the physical activity intervention. The magnitude of change in
weight due to physical activity is additive to that associated with caloric
Is there evidence that physical activity provides benefit for
weight maintenance in adults who have previously lost substantial body
The scientific evidence for the effectiveness of physical activity
alone in preventing weight regain following significant weight loss is limited.
Available data indicate that to prevent substantial weight regain over 6 months
or longer, many adults need to exercise in the range of 60 minutes of walking
or 30 minutes of jogging daily (approximately 4.4 kilocalories per kilogram per
day of activity energy expenditure). The literature generally supports the
concept that "more is better" for long-term weight maintenance following weight
loss. Further, the evidence indicates that individuals who are successful at
long-term weight maintenance appear to limit caloric intake in addition to
maintaining physical activity.
For people who are overweight or obese is there evidence that
physical activity provides health benefits irrespective of assisting with
energy balance?
Yes. Strong evidence shows that physically active adults who are
overweight or obese experience a variety of health benefits that are generally
similar to those observed in people of optimal body weight (BMI = 18.5-24.9).
These benefits include lower rates of all‑cause mortality, coronary heart
disease, hypertension, stroke, type 2 diabetes, colon cancer, and breast
cancer. At least some of these benefits appear to be independent of a loss in
body weight, while in some cases weight loss in conjunction with an increase in
physical activity results in even greater benefits. Because of the health
benefits of physical activity that are independent of body weight
classification, adults of all sizes and shapes gain health and fitness benefits
by being habitually physically active.
What does the evidence indicate about the major physical
fitness and health benefits of physical activity in children and youth?
Strong evidence demonstrates that the physical fitness and health
status of children and youth is substantially enhanced by frequent physical
activity. Compared to inactive young people, physically active children and
youth have higher levels of cardiorespiratory endurance and muscular strength
and well documented health benefits include lower body fatness, more favorable
cardiovascular and metabolic disease risk profiles, enhanced bone health, and
reduced symptoms of anxiety and depression. These conclusions are based on the
results of observational studies in which higher levels of physical activity
were found to be associated with favorable health parameters as well as
experimental studies in which exercise treatments caused improvements in
physical fitness and various health-related factors.
What does the evidence indicate about the dose of physical
activity that is most likely to provide health benefits for children and
Few studies have provided data on the dose response for various
health and fitness outcomes in children and youth. However, substantial data
indicate that important health and fitness benefits can be expected to accrue
to most children and youth who participate daily in 60 or more minutes of
moderate to vigorous physical activity. Also, the Committee concluded that
certain specific types of physical activity should be included in an overall
physical activity pattern in order for children and youth to gain comprehensive
health benefits. These include regular participation in each of the following
types of physical activity on 3 or more days per week: resistance exercise to
enhance muscular strength in the large muscle groups of the trunk and limbs,
vigorous aerobic exercise to improve cardiorespiratory fitness and
cardiovascular and metabolic disease risk factors, and weight-loading
activities to promote bone health.
Is there evidence that the target dose for physical activity
should differ for older adults?
Yes. If a person has a low exercise capacity (physical fitness),
the intensity and amount of activity needed to achieve many health-related and
fitness benefits is less than for someone who has a higher level of activity
and fitness. For example, relative improvements in cardiorespiratory endurance
and muscle strength produced by an increase in physical activity are more
closely associated with the activity intensity relative to the capacity of the
individual (e.g., percent of VO2max or one repetition max [1RM])
than to the absolute intensity of the activity (e.g., 6 miles per hour or 100
pounds). Because the exercise capacity of adults tends to decrease as they age,
older adults generally have lower exercise capacities than younger persons.
Thus, they need a physical activity plan that is of lower absolute intensity
and amount (but similar in relative intensity and amount) than is appropriate
for more fit people, especially when they have been sedentary and are starting
an activity program.
What is the evidence that physical activity in older adults
can reduce or prevent falls?
For older adults at risk of falling, strong evidence exists that
regular physical activity is safe and reduces falls by about 30%. Most evidence
supports a program of exercise with the following characteristics: 3 times per
week of balance training and moderate-intensity muscle-strengthening activities
for 30 minutes per session and with additional encouragement to participate in
moderate-intensity walking activities 2 or more times per week for 30 minutes
per session. Some evidence, albeit less consistent, suggests that tai chi
exercises also reduces falls. Successful reduction in falls by tai chi
interventions resulted from programs conducted from 1 to 3 hours or more per
week. No evidence indicates that planned physical activity reduces falls in
adults and older adults who are not at risk for falls.
Is there evidence that physical activity provides health
benefits to persons with various disabilities?
Yes. However, for many physical and cognitive disabilities,
scientific evidence for various health and fitness outcomes is still limited
due to the lack of research. The goal of the scientific review in persons with
disabilities was not to consider exercise as a therapy for disability but to
evaluate the evidence that physical activity provides the general health and
fitness benefits frequently reported in populations without these disabilities
(e.g., improvements in physical fitness, biomarkers for chronic disease,
physical independence, health-related quality of life). Moderate to strong
evidence indicates that increases in aerobic exercise improve cardiorespiratory
fitness in individuals with lower limb loss, multiple sclerosis, stroke, spinal
cord injury, and mental illness. Limited data show similar results for people
with cerebral palsy, muscular dystrophy, and Alzheimer's disease. Moderate to
strong evidence also exists for improvements in walking speed and walking
distance in patients with stroke, multiple sclerosis, and intellectual
disabilities. Quite strong evidence indicates that resistance exercise training
improves muscular strength in persons with such conditions as stroke, multiple
sclerosis, cerebral palsy, spinal cord injury, and intellectual disability.
Although evidence of benefit is suggestive for such outcomes as flexibility,
atherogenic lipids, bone mineral density, and quality of life, the data are
still very limited.
For a majority of the studies reviewed involving persons with
disabilities, the exercise regimen followed was that currently recommended for
the general public — aerobic exercise of 30 to 60 minutes, 3 to 5 days
per week at moderate intensity, and resistance training with 1 or 2 sets of 8
to 12 repetitions using appropriate muscle groups 2 to 3 times per week
(intensity adjusted for the individual's capacity). Data comparing various
doses of exercise in a single study are not available. In the studies reviewed,
participants had to meet study eligibility and, in some cases, had to have a
pre-participation medical evaluation, but the medical adverse event rate was
low and did not differ between exercise program participants and non-exercise
Is there evidence regarding the health benefits as well as
risks of physical activity for women during pregnancy and the postpartum
Substantial data from observational studies indicates that
moderate-intensity physical activity by generally healthy women during
pregnancy increases cardiorespiratory fitness without increasing the risk of
low birth weight, preterm delivery, or early pregnancy loss. The results of
several studies also indicate that moderate-intensity physical activity does
not increase the risk of preeclampsia. Available data from recent observational
studies show a favorable association between moderate-intensity activity during
early pregnancy and somewhat lower rates of preeclampsia and gestational
diabetes mellitus (GDM), although these data are not yet conclusive. For
moderate-intensity activity during pregnancy, the scientific evidence is strong
that the risks are very low, but the science is less strong in documenting
improved health outcomes for the mother or child. The few studies that have
been conducted on the risks and benefits of vigorous activity by women who are
pregnant provide very limited data that this level of activity is associated
with small reductions in birth weight compared to birth weights of infants born
to less active women.
Moderate-intensity physical activity during the postpartum period
does not appear to adversely affect milk volume or composition or infant
growth, and moderately strong evidence suggests that it results in enhanced
cardiorespiratory fitness and mood of the mother. Physical activity alone does
not produce weight loss except when combined with dietary changes.
Dose-response studies of physical activity and health outcomes for
moderate- or vigorous-intensity physical activity during pregnancy or the
postpartum period have not been conducted. Most studies evaluating possible
benefits have promoted moderate-intensity activity for 120 to 150 minutes per
Is there evidence that the physical activity dose for
improving health and fitness should differ for people depending upon race or
Since 1995, only a limited number of prospective studies
investigating the relation between physical activity and health outcomes have
had adequate samples of non‑Hispanic white men or women and one or more
other race/ethnicities, which would allow a direct comparison of benefits. In
the observational cohort studies with all-cause mortality or cause-specific
chronic disease morbidity and mortality as the outcome and with sufficient
samples sizes and event rates to have reasonable power to detect meaningful
difference between race and ethnic groups, no differences have been reported.
In prospective observational studies conducted in countries where the majority
of the population is other than non-Hispanic white, the generally favorable
relation between higher levels of physical activity and chronic disease events
is similar to many of the studies reporting on non-Hispanic white populations.
In the few experimental studies where aerobic exercise training was the
intervention, no meaningful differences have been reported for changes in
cardiorespiratory fitness, body weight, or cardiovascular disease biomarkers
when comparing non-Hispanic white and African-American men and women. Thus,
based on the currently available scientific evidence, the dose of physical
activity that provides various favorable health and fitness outcomes appears to
be similar for adults of various races and ethnicities.
Continue to F. Scientific Literature Search
Back to C. Key Terms
to Physical Activity Guidelines Advisory Committee
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Physical Activity
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Last updated: 10/22/2019
This site is coordinated by the Office of Disease Prevention and Health Promotion,
Office of the Assistant Secretary for Health, Office of the Secretary,
U.S. Department of Health and Human Services.
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Wood (Jerry Krider, Paul Sumner, Peter Chapman and more)
Large Red Carved Fish
Hand-carved by Paul Sumner, each fish is distinct with personality and incorporates Paul's sense of fun and whimsy. Playing with color, texture and pattern, he creates unique pieces that look great on the wall alone or displayed in "schools."
- Made with: Wood, tin, acrylic paint
- Measures 6"h × 33"l × 1¼"d
- Item #56591
To see more by this artist, follow this link.
Additional Info
About the artist:
Paul is a self-employed woodworker living in Greensboro, North Carolina. He has been in business since 1979 and his work has been shown in galleries nationwide and exhibited in several critically acclaimed shows, such as the Smithsonian Craft Show. Although Paul is a prolific artist, his fish are among his most dynamic works.
Hand-crafted in the U.S.A.
Visit http://creationsgallery.com/offerings.html for more offerings.

subset: commoncrawl


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I read an article online today about how to look more like a
You'd think as an erotic romance author I would regularly wear sexy lingerie or nothing at all to bed. (Do you hear that? It's the sound of Mr. Simone laughing his ass off.)
No. I tend to wear old, stretched out T-shirts and panties to bed. Sometimes I include mismatched socks. Sometimes the shirts are so ugly and worn, Mr. Simone's first comment when he sees me is, "Really, Bec, really?"
I'm thinking I should probably take a cue from my heroines (who always look sexy and fabulous) and upgrade my bedroom wardrobe. What do you think?
What about you? What do you wear to bed?
You can learn more about Becca, her books, and her sexier heroines on her website.


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The structure of La Salle's MBA program is composed of five sections: Foundation, Core, Specialization, Executive Perspectives, and the Integrative Capstone. Students must complete between 33 and 45 credits to complete the MBA at La Salle University. The total amount of credits to fulfill the requirements of the MBA depends upon the student's academic and professional background.
The purpose of the Foundation area of this program is to provide students with a functional knowledge of business theory in the context of decision making and leadership skills. The following three courses (three credits each) are required but may be waived based on a student's academic and professional background.
The Core
The following four courses (three credits each) provide students with practical applications for business leaders in the areas of marketing, accounting, and financial management. Applying our analytical, problem-solving approach to business education, the courses in this area ensure comprehensiveness in the program of studies, expose the student to these areas at a more sophisticated level than most traditional MBA programs, and supply a conceptual framework for the analysis of management decision making.
One specialization is required in the program. Students are required to complete three 700-level courses in one of the following areas. Not all specializations are offered at all locations. Specialization offerings are determined by student interests at each location.
* Those students who wish to design their own specialization may select the General Business Administration area. One must choose any three courses in the 700 level of the program. This option provides the most flexibility in creating an MBA program tailored to a student's interests.
Students may elect to complete a dual specialization as part of their MBA program. Since the variations are many, it is recommended that students meet with an adviser to discuss what would be required to complete such a program.
Executive Perspectives
The following four courses (three credits each) provide students with a greater understanding of what it means to lead ideas and people in an organization. Topics include assessing and developing one's leadership skills, learning how to use technology for managing the vast array of information sources available, and making appropriate decisions and understanding how the financial outlook of an organization might be effected by such decisions.
Integrative Capstone
The capstone course provides the opportunity to integrate what has been learned in the core, specialization, and executive perspective areas while adding other content in business strategy, global perspectives, and ethical/legal dimensions necessary to succeed in the global business arena.


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Spicy Salt & Pepper Chicken Lollipops
8 comments:
One of my favorites is Salt and Pepper Shrimp. Heavily seasoned, rolled in cornstarch and fried. Heaven on a plate. These are great for appetizers - I bet kids would love them!ReplyDelete
Works of art these are! I'll definitely be trying these.ReplyDelete
Picture perfect Mari..:)..We usually make it more spicy with Red chilli or cayenne paper..These look gorgeous..that kitchen towel(hope am right abt that..) n the flower..Abs beautiful dear..:)ReplyDelete
Looks quite tasty Mary! I would love these.ReplyDelete
Mari, they look wonderful ... Thank you for the review of the frozen chicken drumettes.ReplyDelete
The photos is fantastic .... gorgeous, vibrant colors.
Boy does this bring back memories. I loved these when I was a girl. ClariceReplyDelete
Boy does this bring back memories. I loved these when I was a girl. ClariceReplyDelete
always fab mary, ALWAYS! thanks so much for such a darling weekend, i am truly happy to think of you as my friend darling!ReplyDelete


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WASHINGTON (Reuters) - Gun rights groups on Sunday forecast that bids to ban assault weapons and high-capacity ammunition clips would fail in Congress, as Vice President Joe Biden prepares this week to give President Barack Obama proposals to curb gun violence.
Even some congressional Democrats indicated that a bill to revive the U.S. assault weapons ban that expired in 2004 would have a difficult time winning passage in the Republican-controlled House of Representatives and Democratic-led Senate.
"An assault weapons stand-alone ban - on just guns alone ... in the political reality that we have today, will not go anywhere," Democratic Senator Joe Manchin of West Virginia, himself a gun owner, told the CNN program "State of the Union."
National Rifle Association President David Keene signaled little appetite for compromise as the White House considers action on gun violence after the December 14 massacre of 20 children and six adults at a Connecticut elementary school.
"What we put the brakes on is anything that simply takes away a person's Second Amendment right for no good reason," Keene told the CNN show, referring to the U.S. Constitution's guarantee of the right to bear arms.
"The likelihood is that they are not going to be able to get an assault weapons ban through this Congress," Keene said. Asked about new limits on high-capacity ammunition clips, he added: "I don't think ultimately they are going to get that either."
Biden, who heads a task force on gun violence due to give Obama recommendations as early as Tuesday, has said he will recommend universal background checks for gun buyers and new limits on the capacity of magazines like those used by the Connecticut gunman.
Biden and three members of Obama's Cabinet are to meet with members of the Republican-controlled U.S. House of Representatives on Monday as he prepared recommendations on how to curb gun violence in the United States.
The White House also has said it will try to revive the U.S. ban on assault weapons that expired in 2004 after being in effect for a decade. Democratic Senators Dianne Feinstein of California and Richard Blumenthal of Connecticut are expected to introduce legislation on reviving the assault-weapons ban.
The gun control debate has been heating up since the Connecticut massacre. The issue even came up during the Miss America pageant on Saturday night in Las Vegas. Miss New York, Mallory Hytes Hagan, the eventual winner, was asked during the competition whether armed guards should be put in schools.
"I don't think the proper way to fight violence is with violence," Hagan said, indicating that she opposes the idea championed by the NRA after the Newtown massacre.
The NRA has a long history of influence in Washington. It spends heavily on political races and says it has 4 million members. The group criticized the White House effort after meeting with Biden on Thursday.
Appearing on "Fox News Sunday," Larry Pratt, executive director of another gun rights group, Gun Owners of America, said: "We don't think that there is much likelihood that the Congress is going to move on making gun-control laws worse than they are."
Pratt also touted a House Republican lawmaker's proposal to get rid of "gun-free zones" around schools, and asked: "Are we really better off when we say, 'No defense is a good defense?'"
Representative Elijah Cummings, a Maryland Democrat, was cautious about the chances for a revival of the assault weapons ban. He told CNN: "I think that we have a possibility. But I think it's going to be very difficult. I think the things that we do agree on, it seems, (are) the universal background checks and the (limits on) high-capacity magazines."
Biden has been meeting with people on various sides of the issue, including the NRA and gun owners' groups, representatives of the movie and video-game industries and law enforcement.
The background check requirement would extend to all gun purchasers. This would close the "gun-show loophole," in which vendors at open-air gun sales events can sell without a background check on the purchaser. It would also extend to private sales such as those conducted over the Internet.
Reporting by Will Dunham, David Brunnstrom and Patricia Zengerle. Editing by Christopher Wilson


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Boy howdy- got a lot of work to post today. My recent Moleskinning, in no particular order (though most are dated):
My studio. Didn't realize until I got a few comments on Flickr just how many damn guitars there are in there.
Patron at Common Grounds coffee in the Highlands neighborhood, Denver.
Downtown Central City, CO a few months ago. All the historic buildings are casinos now. Yup, all of them.
Michael Grave's addition to the Denver Public Library, with the shadow of Daniel Libeskind's Museum of Art falling across it.
Restaurant in Denver somewhere.
Sketching during my birthday dinner at Deluxe, Denver.
My Ariat Ramblers.
Pedestrian Bridge over Cherry Creek, downtown Denver.
My local Starbucks, Federal and 44th.
This building at Zuni and Dunkeld has a secret health club inside, though the windows are all covered up.
There will be more updates soon, rest assured.


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Andy Ellwood necesitaba un nuevo diseño de logotipo y lanzó un concurso de diseño en 99designs.
2 ganadores han sido elegidos entre 104 diseños de 43 diseñadores freelance.
We want a bright, modern, innovative logo to reflect our personality as company yet convey professionalism and trust. We have just completed a competition and selected an excellent logo, but we want to rerun the competition with a less restrictive brief to encourage your imagination and creativity!!
HiberniaEvros Technology Group (HETG) was formed by the merger of two long standing Irish IT product and services companies in November 2008. We want a logo that reflects the new company working as a fully integrated entity. While our 20 year heritage is important, we want a modern, vibrant logo that conveys professionalism and a modern outlook. It should also be used as a brand mark that people will associate with us.
Company Overview
- Large IT Services Company (approx 80 employees)
- Focus on Infrastructure Architecture, Systems Support, Outsourcing, Managed Services.
- National Irish CoverageType of Customers
- Large Enterprise Customers
- Public and Private Sector
- Companies that feel that the quality of support and resources (people) available are critical in making their decisions about which company to chooseWhat HETG Represents
- Excellence in Technology Solutions and Service
- Pride in our expertise
- A can do attitude
- Team focus and effort
- Work hard but enjoy the work.
- Will go the extra mile to support our clients
- Flexible in our approachStaff Make-Up
- 80% technical
- 20% sales, finance and Admin
- If the design has a separate graphical element to the lettering, we would like versions with the graphical element above the name of the company and to one side (whichever looks best)
- logo must be 2-3 pantone colours, (pantone specified preferably)
- any text must be outlined
- Design to be supplied in both greyscale and colour versions.
- Need High quality (EPS?) version for printing
- Need Hi res JPEG
- Need Lo Res JPEG (for online and presentation use)
- Design must work when large (signage etc) and small (e.g. on business cards)
- The design could be used on print, online, normal word documents, mail franking, embroidery (shirts), engraved (corporate gifts) etc etc so should be equally effective in both colour and black & white/embossed.
- If possible avoid shading (or keep to a minimum) to ensure quality and accuracy of reproduction
Descubre cómo funciona un concurso de diseño u obtén más información sobre nuestros servicios de diseño de logo.


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As part of the Cakespy entry in the Foodbuzz "24 Meals, 24 Cities, 24 Blog Posts" worldwide blogging event, we made just about the sweetest salad ever--here's how to make your own!
We used Merckens Green candy wafers, which can be purchased at cakesnthings.com. Originally we thought that using a leaf mold might work for lettuce (you can see some of them on the bottom layer of the salad), but we discovered this method that worked even better:
Step 1: Melt 'em: You may find that one method works better for you than another. We melted them in the microwave, but many swear by the double-boiler method. Check out the different options here.
Step 2: Spread out a long sheet of plastic wrap (12 inches long or so). On one half of the plastic wrap, spread a 1/3 inch thick layer of the melted confection.
Step 3: Fold the unused portion of the plastic wrap over the candy, and smooth down to a desired thickness (not too thin or it will break!).
Step 4: Wrinkle the still-warm candy gently with your fingers, to give little wrinkles and ripples like on lettuce leaves.
Step 5: Let cool for 20-30 minutes or until solid.
Step 6: Gently uncover. Pieces may break off at the ends, but this is ok--lettuce is abnormally shaped after all!
Garnish as desired (with cake cubes for "croutons", red cookies for tomatoes, etc)


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Supporting Your PPC Campaign with Keyword Analysis
The foundation of all search-engine work is a keyword analysis. Doing a keyword analysis is really not that complicated and can mean the difference between success and failure to your PPC campaign.
Begin by typing the obvious keywords into a text editor or word processor — the ones you've already thought of, or, if you haven't started yet, the ones that immediately come to mind. Then study the list for a few minutes. What else can you add? What similar terms come to mind? Add them, too. Later in your analysis, you'll find that some of these initial terms aren't searched for very often. But that's okay; this list is just a starting point.
Your company name
Include your company name on the list, in whatever permutations you can think of (Microsoft, MS, MSFT, and so on).
Trademarks and product names and terms
Think about all the product names and terms that people may be searching on, even your own trademarked terms if you have any. Don't assume that people will find you anyway, even without PPC; in many cases, the trademark owner does not rank well for the trademarked term. Even if your company does rank near the top, consider whether you want to advertise in the sponsored results, too. Other companies may come above you in the sponsored results, perhaps your partners — agents, retailers, and so on — but also perhaps competitors.
Other companies' names and product names
If people will likely be searching for companies and products similar to yours, add those companies and products to your list for now.
Sometimes similar words are easily missed. If your business is a home-related business, for instance, have you thought about the term house? Americans may easily overlook this word, using home instead, but other English-speaking countries use the word house more frequently than home. Add it to the list because you may find quite a few searches related to it. There are even differences between terms within the United States — in some areas of the country people say soda; in other areas they say pop, for instance — so try to be aware of any differences pertinent to your business.
Split or merged words
You may find that although your product name is one word — RodentRacing, for instance — most people search for you using two words, rodent and racing. Remember to consider your customer's point of view.
Also, some words are employed in two ways. Some people, for instance, use the term knowledgebase, while others use knowledge base. Which is more important? Both should be on your list, but knowledge base is used four to five times more often than knowledgebase.
Singulars and plurals
Go through your list and add singulars and plurals. Search engines treat singulars and plurals differently. For example, searching on rodent and rodents provides different results in both natural and paid search results.
Common combinations
Consider common word combinations. For instance, many people combine the words discount and coupon with product and brand names, and perhaps other terms such as low cost, cheap, and so on.
Hyphenated words
Do you see any hyphenated words on your list that could be used without the hyphen, or vice versa? Some terms are commonly used both ways, so find out what your customers are using. Here are two examples:
- The terms ecommerce and e-commerce are fairly evenly split, with a little over 50 percent of searches using the latter term.
- The dash in e-mail is far less frequently used, with email being the more common term.
Find hyphenated words and add both forms to your list.
Geo-specific terms
Is geography important to your business? Are you selling shoes in Seattle or rodents in Rochester (or rodent shoes in Red Springs)? Don't forget to include terms that include your city, state, other nearby cities, and so on.
Obvious spelling mistakes
Scan through your list and see if you can think of any obvious spelling mistakes. Some spelling mistakes are incredibly important, with 10, 15, or 20 percent of all searches containing the misspelled word, sometimes even more! The word calendar is frequently misspelled. Look at the following list, an estimate of how often the single word calendar is searched for each day in its various permutations:
calendar: 10,605 times calender: 2,721 calander: 1,549 calandar: 256
Thirty percent of all searches on the word calendar are misspelled! One nice thing about misspellings is that competitors often miss them, so you can grab the traffic without much trouble. A keyword that costs several dollars when spelled correctly might cost only a few cents when misspelled.


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Contact For Rates & Specials!
Visit a museum on your vacation. Our Canada galleries showcase some of the most beautiful art in the world. If you are an artist then you will be inspired by a visit to our art museums. See famous works of art firsthand in our art galleries. Our Canada exhibitions home an interesting collection of artifacts and relics. Any history buff will enjoy a trip to our history museums. If you're traveling with the whole family our children museums are a great excursion for kids. Learn about the natural wonders of the world at our science museums. No matter what type of traveler you are a trip is never complete without visiting the local museum. Browse our Canada museums and plan your vacation today!