Effects of short-term exercise in the heat on thermoregulation, blood parameters, sweat secretion and sweat composition of tropic-dwelling subjects
Effects of short-term exercise in the heat on thermoregulation, blood parameters, sweat secretion and sweat composition of tropic-dwelling subjects
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DOI：
10.2114/jpa.24.541
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发表时间：
2005-09-01
期刊：
影响因子：
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通讯作者：
Tochihara, Yutaka
中科院分区：
文献类型：
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作者：
Saat, Mohamed;Sirisinghe, Roland Gamini;Tochihara, Yutaka
本研究调查了炎热环境下的短期有氧训练计划对暴露于被动高温的热带居民的体温调节、血液参数、汗液分泌和成分的影响。 16 名健康的马来西亚马来裔男性志愿者通过在炎热环境（Ta：31.1 +/- 0.1 摄氏度，rh：70.0 +/- 4.4%）中每天在自行车测力计上以 VO(2)max 的 60% 锻炼 60 分钟进行热适应 (HA)，持续 14 天。上述所有参数均在 HA 第一天和 HA 结束时（第 16 天）记录。这两天，受试者休息 10 分钟，然后以 VO(2)max 的 60% 循环 60 分钟，然后在简易加热室中再次休息 20 分钟（恢复）。测试期间记录直肠温度（T-rc）、平均皮肤温度（T-sk）心率（HR）、感知用力等级（RPE）、热感觉（TS）、局部出汗率和脱水百分比。分析汗液浓度中的钠 [Na+]（汗液）和钾。分析血样的生化变化、电解质和血液学指标。每次测试前后收集尿液样本并分析电解质。适应期后，运动期间的脱水百分比从 1.77 +/- 0.09%（第 1 天）显着增加到 2.14 +/- 0.07%（第 16 天）。血红蛋白、血细胞比容和红细胞的静息水平显着下降，而[Na+]（汗液）显着增加。对于 T-rc 和 T-sk 来说，休息时没有差异。适应期后，运动第 40 分钟的 T,e、HR、RPE、TS、血浆乳酸浓度、血红蛋白和红细胞压积显着降低，但平均红细胞血红蛋白和血清渗透压显着升高，而 [Na+]（汗液）和 T-sk 没有差异。可以得出的结论是，居住在热带地区的受试者虽然暴露于长时间的被动热暴露，但并未完全适应热环境。为了进一步实现HA，他们应该在炎热的环境中逐渐暴露在运动热应激下。
This study investigates the effects of a short-term aerobic training program in a hot environment on thermoregulation, blood parameters, sweat secretion and composition in tropic-dwellers who have been exposed to passive heat. Sixteen healthy Malaysian-Malay male volunteers underwent heat acclimation (HA) by exercising on a bicycle ergometer at 60% of VO(2)max for 60min each day in a hot environment (Ta: 31.1 +/- 0.1 degrees C, rh: 70.0 +/- 4.4%) for 14 days. All parameters mentioned above were recorded on Day I and at the end of HA (Day 16). On these two days, subjects rested for 10 min, then cycled at 60% of VO(2)max for 60 min and rested again for 20min (recovery) in an improvised heat chamber. Rectal temperature (T-rc), mean skin temperature (T-sk) heart rate (HR), ratings of perceived exertion (RPE), thermal sensation (TS), local sweat rate and percent dehydration were recorded during the test. Sweat concentration was analysed for sodium [Na+](sweat) and potassium. Blood samples were analysed for biochemical changes, electrolytes and hematologic indices. Urine samples were collected before and after each test and analysed for electrolytes.After the period of acclimation the percent dehydration during exercise significantly increased from 1.77 +/- 0.09% (Day 1) to 2.14 +/- 0.07% (Day 16). Resting levels of hemoglobin, hematocrit and red blood cells decreased significantly while [Na+](sweat) increased significantly. For T-rc and T-sk there were no differences at rest. T,e, HR, RPE, TS, plasma lactate concentration, hemoglobin and hematocrit at the 40th min of exercise were significantly lower after the period of acclimation but mean corpuscular hemoglobin and serum osmolality were significantly higher while no difference was seen in [Na+](sweat) and T-sk. It can be concluded that tropic-dwelling subjects, although exposed to prolonged passive heat exposure, were not fully heat acclimatized. To achieve further HA, they should gradually expose themselves to exercise-heat stress in a hot environment.