Comparison of exercise training and repeated hot water immersion on vascular function in overweight older adults

Recent studies suggest that heat exposure may benefit cardiovascular health, but in overweight and obese older adults, the chronic effects of heat therapy on artery function are still uncertain. We aimed to compare the effects of 12 weeks (3×/week, 40 min) of aerobic exercise (EXE) to hot water immersion (HWI) and an inactive control group (CON), on vascular function. Thirty-one inactive older adults (58 ± 7years; 30.1 ± 3.8 kg/m²) were randomly assigned into three groups: EXE (cycle ergometry, n = 11), HWI (40°C, n = 11) or an inactive CON group (n = 9). Resting blood pressure (BP), pulse wave velocity (PWV; Sphygmocor), and flow-mediated dilation (FMD%) and glyceryl trinitrate-induced dilation (GTN%) in the brachial and femoral arteries (Doppler ultrasound) were assessed at baseline and after 12 weeks. The groups were matched for age, BMI and clinical parameters. For brachial FMD%, an interaction effect (P = 0.014) was observed, with post hoc analysis indicating that the increases observed in the EXE and HWI groups did not differ significantly, whereas the EXE group increased significantly more than CON. For femoral FMD%, an interaction effect (P = 0.047) indicated that the EXE group increased more than CON, with no difference between HWI and CON. Brachial and femoral GTN%, resting BP and PWV showed no main or interaction effect. These data suggest that 12 weeks of moderate aerobic exercise induces brachial and femoral artery endothelial function benefits relative to an inactive control group of older individuals with overweight and obesity, that brachial responses increased in response to both EXE and HWI, and the changes induced by exercise and hot water immersion did not statistically differ.