Acute flywheel exercise does not impair the brachial artery vasodilation in healthy men of varying aerobic fitness.

BACKGROUND The cardiovascular response to variable load exercise on a flywheel ergometer is still unknown. OBJECTIVE This study examined the effects of flywheel exercise on cardiovascular response and brachial artery vasodilation capacity in healthy, active men. METHODS In this cross-sectional study, nineteen men (20-57 years old) completed three laboratory visits, including a ramp exercise test to determine their maximal oxygen uptake VO2 max, and exercise intervention on a flywheel ergometer set at 0.075 kg·m2 moment of inertia. After the ramp test cessation, all participants were allocated into aerobically untrained (n = 10) and trained (n = 9) groups. Throughout the flywheel exercise, cardiovascular demands were continuously monitored via Finapres, while a pre/postflow-mediated dilation (FMD) assessment was performed using ultrasound imaging. RESULTS There were no differences observed between the groups in their anthropometrics, age or resting brachial artery diameter, while the VO2 max was ~15% higher (P = 0.001) in trained compared to aerobically untrained group. The cardiovascular response to the flywheel exercise was similar between the groups, with peak mean arterial pressure and heart rate readings reaching ~160 mmHg and ~140 bpm, respectively. The flywheel exercise did not impair the FMD (%) response, which was comparable between the groups (P = 0.256). When these data were pooled, the regression analysis showed an inverse relationship among FMD (%), age (β = -0.936, P = 0.001) and VO2 max. (β = -0.359, P = 0.045). CONCLUSION Although aerobic fitness alone does not directly explain the FMD response to flywheel exercise, aerobically untrained individuals, as they get older, tend to have lower brachial artery FMD.