The effect of seasonal acclimatization on whole body heat loss response during exercise in a hot humid environment with different air velocity
The effect of seasonal acclimatization on whole body heat loss response during exercise in a hot humid environment with different air velocity
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不同风速湿热环境下季节适应对运动时全身失热反应的影响
DOI：
10.1152/japplphysiol.00837.2020
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发表时间：
2021
影响因子：
3.3
通讯作者：
Kondo Narihiko
中科院分区：
文献类型：
--
作者：
Lei Tze-Huan;Fujiwara Masashi;Gerrett Nicola;Amano Tatsuro;M?ndel Toby;Inoue Yoshimitsu;Okushima Dai;Nishiyasu Takeshi;Kondo Narihiko
已知从冬季到夏季的季节性适应可增强运动期间干热环境中的热效应器响应，而其对湿热环境中汗液蒸发和核心温度（Tcore）响应的影响仍未知。因此，我们试图确定季节性适应是否能够调节全身出汗率（WBSR），蒸发出汗率，出汗效率和体温调节功能，在湿热环境（32°C，75%RH）中进行自行车运动。我们还确定了是否增加空气流速可以提高蒸发汗率和出汗效率之前和之后的季节习服。12只雄性动物在冬季（适应前）以40%V ~ 2 max循环1 h，并在夏季（适应后）再次重复试验。对于最后20分钟的骑自行车在稳定状态的Tcore，空气速度增加从0.2（0.04）米/秒到1.1（0.02）米/秒，通过使用位于前面的参与者的电风扇。季节性习服使WBSR、未蒸发汗率、局部出汗率和平均皮温均高于习服前（均P < 0.05），而出汗效率低于习服前（P< 0.01）。训练状态对Tcore和发汗率无明显影响（P> 0.70）。总之，季节性习服增强热效应反应，但不减弱Tcore在运动过程中在湿热环境。此外，增加空气速度提高蒸发的汗水率和出汗效率，而不管适应状态。新&值得注意的是季节性适应湿热增强外分泌汗腺功能，从而导致更高的局部和全身出汗率，但不会削弱Tcore在运动过程中在湿热环境。与适应前相比，在增加和不增加空气流速的情况下，季节性湿热习服后的出汗效率较低。然而，具有较低的出汗效率不会减轻在湿热环境中运动期间的Tcoreresponse。
Seasonal acclimatization from winter to summer is known to enhance thermoeffector responses in hot-dry environments during exercise whereas its impact on sweat evaporation and core temperature (Tcore) responses in hot-humid environments remains unknown. We, therefore, sought to determine whether seasonal acclimatization is able to modulate whole body sweat rate (WBSR), evaporated sweat rate, sweating efficiency, and thermoregulatory function during cycling exercise in a hot-humid environment (32°C, 75% RH). We also determined whether the increase in air velocity could enhance evaporated sweat rate and sweating efficiency before and after seasonal acclimatization. Twelve males cycled for 1 h at 40% V̇o2maxin winter (preacclimatization) and repeated the trial again in summer (after acclimatization). For the last 20 min of cycling at a steady-state of Tcore, air velocity increased from 0.2 (0.04) m/s to 1.1 (0.02) m/s by using an electric fan located in front of the participant. Seasonal acclimatization enhanced WBSR, unevaporated sweat rate, local sweat rate and mean skin temperature compared with preacclimatization state (allP< 0.05) whereas sweating efficiency was lower (P< 0.01) until 55 min of exercise. Tcoreand evaporated sweat rate were unaltered by acclimatization status (allP> 0.70). In conclusion, seasonal acclimatization enhances thermoeffector responses but does not attenuate Tcoreduring exercise in a hot-humid environment. Furthermore, increasing air velocity enhances evaporated sweat rate and sweating efficiency irrespective of acclimated state.NEW & NOTEWORTHYSeasonal acclimatization to humid heat enhances eccrine sweat gland function and thus results in a higher local and whole body sweat rate but does not attenuate Tcoreduring exercise in a hot-humid environment. Sweating efficiency is lower after seasonal acclimatization to humid heat compared with preacclimatization with and without the increase of air velocity. However, having a lower sweating efficiency does not mitigate the Tcoreresponse during exercise in a hot-humid environment.