Effect of moderate-intensity treadmill exercise under different ambient temperatures on peripheral circulatory responses in young healthy adults

Exercise training has the potential for inducing enhancements in peripheral circulation, which can play important preventive and therapeutic roles in peripheral circulatory diseases. However, the relevant published studies show conflicting and inconclusive results. Furthermore, useful or optimum ambient temperature for this purpose has not yet been established. Therefore, we investigated the acute responses in peripheral circulation from exposure of healthy subjects to treadmill exercise under different ambient temperatures; A total of 12 young adult volunteers (males 6, females 6) randomly underwent three sessions of treadmill exercise for 30 min under three different ambient temperatures (10°C, 20°C, and 30°C), at a predetermined exercise intensity. Before and after the intervention, leg skin blood flow (SBF) was measured by laser speckle flowgraphy and hand skin temperature (ST), by digital thermometry; After the cessation of treadmill exercise, compared to the corresponding baseline values, a significant increase in SBF was observed under all ambient temperature conditions (P<0.005). During intervention, ST showed a significant decrease at 10th min of intervention under all ambient temperatures (P<0.005) with a subsequent increasing trend in it. After intervention, a significant increase in ST was observed under 20°C condition only (P<0.05). Also, after intervention, the observed increase in systolic blood pressure was less significant under 20°C condition; Treadmill exercise appears to be a useful intervention modality in inducing improvements in peripheral circulation. However, exposure to treadmill exercise at or near 20°C ambient temperature might be recommended for the purpose.