Acute effects of walking in water on vascular endothelial function and heart rate variability in healthy young men.
AIM
Aquatic exercise might improve endothelial function due to hydrostatic pressure increasing blood flow and causing shear stress to the endothelium. However, the acute effect of aerobic exercise in water on endothelial function is unclear. The present study compares the acute effect of aerobic exercise at moderate intensity in water and on land on endothelial function.


METHODS
Nine healthy young men walked on a treadmill for 30 min while immersed in water up to the xiphoid at 30.0 ± 0.2°C and on land at an intensity equivalent to 60% heart rate reserve in a crossover trial. Brachial artery flow-mediated dilation (FMD) was measured at baseline and at 30 and 60 min after exercise. Autonomic nervous activity was compared among conditions at the heart rate variability (HRV) during exercise.


RESULTS
FMD significantly decreased at 30 min after exercise on land trial (p < 0.05), but did not change after the aquatic trial. However, FMD was significantly higher after aquatic trial than land trial (p < 0.05) at 30 and 60 min after exercise, whereas heart rate, blood pressure, and HRV did not significantly differ between them.


CONCLUSION
These findings demonstrate that aerobic exercise in water suppressed the decrease in FMD compared with that on land, regardless of autonomic nervous activity.
['Hashimoto|Yuto|Y|http://orcid.org/0000-0003-2705-1601', 'Okamoto|Takanobu|T|http://orcid.org/0000-0003-1978-2455']
D001794:Blood Pressure D001916:Brachial Artery D018592:Cross-Over Studies D004730:Endothelium, Vascular D005080:Exercise Test D064368:Healthy Volunteers D006339:Heart Rate D006801:Humans D007101:Immersion D008297:Male D011897:Random Allocation D014664:Vasodilation D016138:Walking D014867:Water D055815:Young Adult
endothelial function heart rate variability aquatic exercise Aerobic exercise vasodilation