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Arterial stiffness acute changes following aerobic exercise in males with and without hypertension

Abstract While regular exercise exposure is considered the most effective therapy to reduce arterial stiffness, the effect of acute exercise training on arterial stiffness in adults with different blood pressure (BP) levels remains unclear. The authors aimed to investigate the effects of acute aerobic exercise on arterial stiffness in male with different BP levels. This cross‐sectional study utilized data for 1200 males aged 20–49 years from the Kailuan study cohort who participated in the fifth National Fitness Monitoring project. A total of 940 participants (621 in the non‐hypertensive group and 319 in the hypertensive group) aged 36.82 ± 7.76 who completed a twice‐quantitative cycle ergometer exercise and measure of brachial‐ankle pulse wave velocity (baPWV) at both the baseline and immediately after exercise were included in this study. The baPWV was decreased after acute aerobic exercise in the non‐hypertension and hypertension groups (Δ 40.29 [95% confidence interval [CI], −47.72 to −32.86] vs. Δ20.45 [95% CI, −31.32 to −9.58] cm/s). Participants without hypertension showed a greater decrease in baPWV (Δ 19.84 [95% CI, −33.83 to −5.84] cm/s) than participants with hypertension. Aerobic exercise had an acute positive effect on arterial stiffness. This study provides evidence of a greater reduction in arterial stiffness in individuals without hypertension than in those with hypertension.

subjects. A study of 61 elderly patients with hypertension showed elevated carotid-femoral pulse wave velocity (cfPWV) immediately after acute maximal exercise compared with baseline levels. 10 And the other investigations in nine hypertensive patients also showed no change in arterial stiffness indices immediately following maximum aerobic exercise. 11 These studies had small sample sizes and were mostly limited to Caucasian populations. To the best of our knowledge, no studies have investigated and compared the effect of acute aerobic exercise-induced changes on arterial stiffness in Asian men with different blood pressure (BP) levels.
Thus, we aimed to evaluate short-term changes in brachial-ankle pulse wave velocity (baPWV) following an acute aerobic exercise test in men with different BP levels in the Kailuan study population who participated in the fifth National Fitness Monitoring.

Subjects
The baPWV was measured before and immediately after each cycling exercise session. The study was carried out in accordance with the guidelines of the Declaration of Helsinki. All participants provided written informed consent to the study, which was approved by the Kailuan General Hospital Ethics Committee.
In this study, we included the following participants: (1) those who had participated in the survey in 2018-2020 and had participated in the fifth National Physique Monitoring; and (2) those who had undergone cycling exercise and had baPWV measured at both the baseline and follow-up exercise.

Exercise protocol
The procedure of performing cycling exercises complies with the Exercise Standards for Testing and Training released by the American Heart Association (AHA) and is briefly described below. 12 All interventions and measurements were performed in a quiet, temperature-controlled

Data collection
Demographic data, lifestyle factors (e.g., age, smoking status, alcohol use, and physical activity), and medical history (e.g., anti-hypertensive and hypoglycemic agents) were collected using a self-reported questionnaire, as detailed previously. 17 Height, weight, and waist circumference were measured by trained nurses, and body mass index (BMI) was calculated as weight (kg)/height 2 (m 2 ). Hypertension was defined as systolic BP ≥140 mmHg, diastolic BP ≥90 mmHg, or use of antihypertensive medications. 18 The definition of diabetes mellitus was laboratory based, with fasting blood glucose levels ≥7.0 mmol/L combined with medication use. 19,20 The smoking status was defined as smoking at least one cigarette/day on average in the past 6 months.
The drinking status was defined as 100 ml/day on average for more than 1 year. Physical activity was defined as aerobic exercise three times/week for ≥30 min periodically.

Statistical analysis
Normally distributed variables are shown as the mean and standard In the multivariate models, we adjusted for baseline baPWV in Model 1. In Model 2, we further adjusted for age (years), BMI (continuous), smoking status (never or ever-smoker), drinking status (never or ever-drinker), and physical activity (never or active). In Model 3, we further adjusted for the changes in HR (exercise minus baseline), changes in brachial MAP (post-exercise minus baseline), VO 2 max and duration of the interval between measurements.
We performed several sensitivity analyses to assess the robustness of our findings. First, we excluded participants with diabetes mellitus, which is associated with a high baPWV and is a potential risk factor for arterial stiffness. To reduce the effect of the interval duration, we also conducted another sensitivity analysis by excluding participants with an interval duration between measurements greater than the 95% quantile (26.7 min). Since the proportion of physical activity was lower in the hypertension group, which is the first line of therapy for hypertension and positive effects of bapwv, we performed an analysis comparing the arterial stiffness response to cycling exercise among physical activity groups (inactive and active groups). Lastly, we performed a sensitivity analysis to adjust for the time of day of assessment which was may influence model results. SAS (version 9.4; SAS Institute, Inc., Cary, NC, USA) was used for all statistical analyses.  (Table 3).

Baseline characteristics
In sensitivity analyses, the change in baPWV from baseline to postexercise in participants in the non-hypertension and hypertension groups, and differences between the groups, remained consistent after excluding participants with diabetes mellitus (Supplementary Note: △(changes) from baseline comparisons;△HR,△Brachial MAP, postexercise minus baseline;. Model 1 is adjusted for baseline baPWV. Model 2 is adjusted for baseline baPWV, age(year), BMI, smoking status (never or ever-smoker), drinking status (never or ever drinker), and physical activity (inactive or active). Model 3 is adjusted for baseline baPWV, age(year), BMI, smoking status (never or ever-smoker), drinking status (never or ever drinker), physical activity (inactive or active), △HR, △Brachial MAP, VO 2 max, and interval measurement duration. Abbreviations: BMI, body mass index; HR, heart rate; MAP, mean arterial pressure; VO 2 max: VO 2 max: maximum oxygen consumption.

DISCUSSION
In the present study, we found that 7 min of cycling exercise was effective in reducing arterial stiffness in male with and without hypertension. Remarkably, the beneficial effects of exercise on arterial stiffness appeared to be more evident in male without hypertension than in those with hypertension.
Age-related differences in arterial stiffness are diminished in healthy individuals who undertake regular exercise. 21 Following a 7min bout of exercise, we also observed a significant reduction in baPWV of 44.90 cm/s from resting values in young and middle-aged (36.82 ± 7.76 years) participants without hypertension. This reduction remained consistent after adjusting for potential confounders.
In line with our results, a previous study conducted by Kingwell and colleagues 22 reported a significant decrease in femoral pulse wave velocity 30 min after a single bout of cycling at 65% of the maximal oxygen uptake in 12 young (24 ± 6 years) healthy men.
Importantly, in our study, baPWV of participants with hypertension was immediately decreased by 11.46 cm/s after exercise compared to that pre-exercise. However, Cooke and colleagues 10 showed elevated cfPWV 3 min after a maximal treadmill exercise test compared with baseline levels in elderly adults with hypertension. A similar finding was also reported by Lefferts and colleagues 23 The greater reflected wave amplitude during exercise in older subjects (>50 years) is due to increased large artery stiffness and impaired vasodilatory capacity in association with the aging process. 24 Discrepancies in findings between this study and the above-mentioned studies could partly be explained by the age difference. Notably, different from the above-mentioned studies, our study used baPWV as the measurement methodology for arterial stiffness. It has been found that immediately post-exercise (0-5 min), the central and upper body arterial segments show an overall increase in arterial stiffness whereas, measurements taken in lower limb segments (proximal to the primary working muscles in most cases) show an immediate decrease in arterial stiffnes. 25 In our study, we further compared the arterial stiffness response to cycling exercise between individuals with and without hypertension.
Both groups showed a significant reduction in baPWV following cycling exercise compared with baseline measurements. Participants without hypertension had a greater reduction (19.84 cm/s) in baPWV than those with hypertension. In contrast to our study, Lefferts and colleagues 23 reported that no obvious differences between middle-aged adults with hypertension and without hypertension were observed in hemodynamic response following exercise. The difference of the participant's health status may be the major contributor to the discrepancies between the two studies. In the study conducted by Lefferts and colleagues, 23 there was no significant difference in health status between participants with and without hypertension, including physical activity, traditional cardiovascular disease profiles, and body composition. Moreover, in this study, BP in their participants with hypertension was well controlled according to at-home BP values.
However, in our study, age and RHR in subjects with hypertension were higher than subjects without hypertension. Accumulative evidences have indicated that an older age 3 and increased RHR 26 are independently associated with vascular aging. Therefore, we speculate that the between-group difference in baPWV after cycling exercise may be related to the above-mentioned factors (age and RHR) attenuating the benefit of exercise on arterial stiffness in participants with hypertension.
Each is slightly shorter than that in previous reports, but the maximum peak HR of the subjects was close to the sub-maximal HR.

CONCLUSIONS
This study suggests that acute aerobic exercise favorably affects endothelial function. We also provide evidence of a greater decrease in arterial stiffness in male individuals without hypertension than in those with hypertension.

Perspectives
In this study, we showed the beneficial effects of acute aerobic exercise by reducing arterial stiffness in young and middle-aged males with and without hypertension. Future studies are warranted to address whether acute aerobic exercise can prevent or delay the onset of early vascular aging, benefit BP control, and how acute exercise influences the human metabolome.

ACKNOWLEDGMENTS
We thank all the survey teams of the Kailuan Study Group for their contribution and the study participants who contributed their information.
No funding.

CONFLICTS OF INTEREST
There are no conflicts of interest.

SUPPORTING INFORMATION
Additional supporting information may be found in the online version of the article at the publisher's website.