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The relationship between %HRpeak and %VO2peak in patients with chronic obstructive pulmonary disease.

PURPOSE
The relationship between the percent peak oxygen consumption (%VO2peak) and percent peak heart rate (%HRpeak) has been suggested as a method for exercise prescription. According to the American College of Sports Medicine (ACSM), 50, 60, 80, and 85% of VO2peak represent 62, 70, 85, and 90% of HRpeak, respectively. Recent research with young healthy adults has shown that this relationship is not as ACSM suggests. Furthermore, it has been suggested that this relationship be examined in populations with low functional capacity.


METHODS
The present study evaluated the relationship between %HRpeak and %VO2peak in 125 patients with chronic obstructive pulmonary disease before and then after 3 months of exercise intervention.


RESULTS
The mean percentages of HRpeak for the COPD patients at baseline were 70, 76, 87, and 90% at 50, 60, 80, and 85% of VO2peak. Percentages of HRpeak at 50, 60, and 80% of VO2peak were significantly different from those suggested by ACSM. The mean percentages of HRpeak after the 3-month exercise intervention were 71, 77, 87, and 90% at 50, 60, 80, and 85% of VO2peak. Percentages of HRpeak at 50, 60, and 80% of VO2peak were significantly different from those suggested by ACSM. There were no significant differences between the slopes and the intercepts of the two equations used to describe the relationship between %HRpeak and %VO2peak. Therefore, we pooled the data from the pre- and post-intervention tests to form the following equation to describe the relationship between %HRpeak and %VO2peak for COPD patients: %HRpeak = 0.55 (+/- 0.01)%VO2peak + 43.2 (+/- 1.4).


CONCLUSION
In conclusion, the relationship between %HRpeak and %VO2peak described by ACSM is not applicable to patients with COPD. Furthermore, this relationship does not change with exercise training and can be described by a single equation.