Postgraduate Program in Exercise Science and Sports, University of Rio de Janeiro State, Rio de Janeiro, Brazil.
Laboratory of Physical Activity and Health Promotion, University of Rio de Janeiro State, Rio de Janeiro, Brazil.
Eur J Appl Physiol. 2020 May;120(5):1001-1013. doi: 10.1007/s00421-020-04340-6. Epub 2020 Mar 18.
To investigate the effect of heat stress on postexercise hypotension.
Seven untrained men, aged 21-33 years, performed two cycling bouts at 60% of oxygen uptake reserve expending 300 kcal in environmental temperatures of 21 °C (TEMP) and 35 °C (HOT) in a randomized, counter-balanced order. Physiological responses were monitored for 10-min before and 60-min after each exercise bout, and after a non-exercise control session (CON). Blood pressure (BP) also was measured during the subsequent 21-h recovery period.
Compared to CON, systolic, and diastolic BPs were significantly reduced in HOT (Δ = - 8.3 ± 1.6 and - 9.7 ± 1.4 mmHg, P < 0.01) and TEMP (Δ = - 4.9 ± 2.1 and - 4.5 ± 0.9 mmHg, P < 0.05) during the first 60 min of postexercise recovery. Compared to TEMP, rectal temperature was 0.6 °C higher (P = 0.001), mean skin temperature was 1.8 °C higher (P = 0.013), and plasma volume (PV) was 2.6 percentage points lower (P = 0.005) in HOT. During the subsequent 21-h recovery period systolic BP was 4.2 mmHg lower in HOT compared to CON (P = 0.016) and 2.5 mmHg lower in HOT compared to TEMP (P = 0.039).
Exercise in the heat increases the hypotensive effects of exercise for at least 22 h in untrained men with elevated blood pressure. Our findings indicate that augmented core and skin temperatures and decreased PV are the main hemodynamic mechanisms underlying a reduction in BP after exercise performed under heat stress.
研究热应激对运动后低血压的影响。
7 名未经训练的男性，年龄 21-33 岁，在环境温度为 21°C（TEMP）和 35°C（HOT）的情况下，以 60%的摄氧量储备进行两次自行车运动，消耗 300 千卡热量。以随机、平衡的顺序进行。在每次运动后 10 分钟和 60 分钟以及非运动对照（CON）后监测生理反应。血压（BP）也在随后的 21 小时恢复期内进行测量。
与 CON 相比，HOT（Δ= -8.3±1.6 和 -9.7±1.4 mmHg，P<0.01）和 TEMP（Δ= -4.9±2.1 和 -4.5±0.9 mmHg，P<0.05）在运动后恢复的前 60 分钟内，收缩压和舒张压均显著降低。与 TEMP 相比，直肠温度高 0.6°C（P=0.001），平均皮肤温度高 1.8°C（P=0.013），血浆体积（PV）低 2.6 个百分点（P=0.005）。在随后的 21 小时恢复期内，HOT 组的收缩压比 CON 组低 4.2mmHg（P=0.016），比 TEMP 组低 2.5mmHg（P=0.039）。
在未训练的高血压男性中，热应激下的运动使运动后的低血压效应至少持续 22 小时。我们的发现表明，核心和皮肤温度升高以及 PV 降低是热应激下运动后血压降低的主要血液动力学机制。
