Modulation of vascular function follows an exercise intensity–dependent pattern in young adults. This study aimed to investigate the potential intensity–dependent effects of an acute bout of exercise on conduit and resistance artery function in healthy older adults.
Eleven healthy older adults (five males/six females, 66 ± 1 yr) completed 30 min of recumbent cycling at 50%–55% (low intensity) and 75%–80% (high intensity) of their age-predicted HRmax on two separate study visits. Doppler ultrasound measures of brachial artery flow-mediated dilation (FMD) and reactive hyperemia were taken at baseline, 10 min postexercise, and 1 h postexercise. In addition, cardiovascular hemodynamics and brachial shear rate were measured every 5 min during exercise.
Brachial artery FMD was enhanced 10 min after high-intensity exercise (4.8% ± 0.2% to 9.1% ± 0.3%, P < 0.01), but not low-intensity (4.7% ± 0.2% to 6.2% ± 0.3%, P = 0.54) exercise. Peak and total (area under the curve) blood flow during reactive hyperemia (measures of resistance artery function) were enhanced 10 min postexercise for both intensities (peak low intensity, 372 ± 31 to 444 ± 37 mL·min−1; peak high intensity, 391 ± 30 to 455 ± 28 mL·min−1; total low intensity, 142 ± 16 to 205 ± 20 mL; total high intensity, 158 ± 14 to 240 ± 25 mL; main effect of time for both, P < 0.05). However, the magnitude of change in peak and the total blood flow were not different between exercise intensities (interaction effect; P = 0.56 and P = 0.97, respectively). Independent of exercise intensity, FMD returned to baseline 1 h after exercise (high, 5.9% ± 0.3%; low, 5.1% ± 0.1%; both P > 0.05).
Our data indicate that high-intensity exercise acutely enhances conduit artery function in healthy older adults. In addition, an acute bout of exercise enhances resistance artery function independent of intensity.
1Human Integrative and Cardiovascular Physiology Laboratory, Department of Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, IA; 2School of Health Sciences, Sapporo Medical University, Sapporo, JAPAN; 3Abboud Cardiovascular Research Center, University of Iowa, Iowa City, IA, 4Fraternal Order of Eagles Diabetes Research Center, Carver College of Medicine, University of Iowa, Iowa City, IA
Address for correspondence: Darren P. Casey, Ph.D., Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, University of Iowa, Iowa City, IA 52242; E-mail: email@example.com.
Submitted for publication June 2017.
Accepted for publication August 2017.