Horiuchi Masahiro, Oliver Samuel J
Division of Human Environmental Science, Mount Fuji Research Institute, Japan; Faculty of Sports and Life Science, National Institute of Fitness and Sports in KANOYA, Japan.
Institute for Applied Human Physiology, College of Human Sciences, Bangor University, Bangor, Wales, UK.
J Therm Biol. 2023 Oct;117:103683. doi: 10.1016/j.jtherbio.2023.103683. Epub 2023 Aug 11.
This research examined the effects of exercising in a hot compared to a temperate environment on post-exercise hemodynamics in untrained men. We hypothesized exercise in a hot compared to a temperate environment would elicit greater post-exercise hypotension, and this would be attributable to higher cutaneous vascular conductance and sweat loss, and lower heart rate variability (HRV) and cardiac baroreflex sensitivity (cBRS). In a randomized counterbalanced order, 12 untrained healthy men completed two trials involving 40-min leg-cycling exercise at either 23 °C (CON) or 35 °C (HOT). Post-exercise participants rested supine for 60 min at 23 °C whilst hemodynamic and thermoregulatory measurements were assessed. Post-exercise hypotension was greater after exercising in a hot than a temperate environment as indicated by a lower mean arterial pressure at 60 min recovery (CON 83 ± 5 mmHg, HOT 78 ± 5 mmHg, Mean difference [95% confidence interval], -5 [-8, -3] mmHg). Throughout recovery, cutaneous vascular conductance was higher, and cBRS and HRV were lower after exercising in a hot than in a temperate environment (P < 0.05). Sweat loss was greater on HOT than on CON (P < 0.001). Post-exercise hypotension after exercising in the hot environment was associated with sweat loss (r = 0.66, P = 0.02), and changes in cutaneous vascular conductance (r = 0.64, P = 0.03), and HRV (Root mean square of the successive difference in R-R interval [RMSSD]) r=0.75, P = 0.01 and and log high frequency [HF] r=0.66, P = 0.02), but not cBRS (all, r ≤ 0.2, P > 0.05). Post-exercise hypotension was greater after exercise in a hot compared to a temperate environment and may be partially explained by greater sweat loss and cutaneous vascular conductance, and lower HRV.
本研究调查了在炎热环境与温和环境中运动对未经训练男性运动后血液动力学的影响。我们假设，与在温和环境中运动相比，在炎热环境中运动会引发更严重的运动后低血压，这可能归因于更高的皮肤血管传导率和出汗量，以及更低的心率变异性（HRV）和心脏压力反射敏感性（cBRS）。12名未经训练的健康男性按照随机平衡顺序完成了两项试验，分别在23°C（CON）或35°C（HOT）下进行40分钟的腿部自行车运动。运动后，参与者在23°C下仰卧休息60分钟，同时评估血液动力学和体温调节指标。运动后60分钟恢复时，平均动脉压较低表明，在炎热环境中运动后比在温和环境中运动后运动后低血压更严重（CON组83±5 mmHg，HOT组78±5 mmHg，平均差异[95%置信区间]，-5 [-8, -3] mmHg）。在整个恢复过程中，与在温和环境中运动相比，在炎热环境中运动后皮肤血管传导率更高，cBRS和HRV更低（P<0.05）。HOT组的出汗量大于CON组（P<0.001）。在炎热环境中运动后的运动后低血压与出汗量（r = 0.66，P = 0.02）、皮肤血管传导率变化（r = 0.64，P = 0.03）以及HRV（R-R间期连续差值的均方根[RMSSD]）（r = 0.75，P = 0.01）和对数高频[HF]（r = 0.66，P = 0.02）有关，但与cBRS无关（所有r≤0.2，P>0.05）。与在温和环境中运动相比，在炎热环境中运动后运动后低血压更严重，这可能部分由更大的出汗量、皮肤血管传导率以及更低的HRV来解释。
