Human thermoregulatory responses during prolonged walking in water at 25, 30 and 35°C
Human thermoregulatory responses during prolonged walking in water at 25, 30 and 35°C
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在 25、30 和 35°C 的水中长时间行走时人体的体温调节反应
DOI：
10.1007/s004210050448
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发表时间：
1998
期刊：
影响因子：
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通讯作者：
K. Fujishima
中科院分区：
文献类型：
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作者：
Tomihiro Shimizu;M. Kosaka;K. Fujishima
8名健康、身体素质良好的男大学生在实验室的跑步机上进行60 min的运动，同时将其浸泡在水中至胸部中部。调整水流速度，使运动强度对应于每个受试者的50%最大摄氧量，并在三个水温：25、30、35°C中的每一个下进行一次实验，然后在25°C的空气中进行30分钟的控制期，并在25°C的环境温度下在空气中的跑步机上进行实验。通过测量不同点的直肠温度和皮肤温度来确定休息和运动期间的热状态，并计算平均皮肤温度。通过测量耗氧量来监测运动强度，并监测心率作为心血管功能的指标。在每种水温下，运动期间都达到了相同的耗氧量水平，这表明在最低水温下颤抖不会产生额外的热量。运动时直肠温度的轻微升高不受水温的影响。暴露于空气中的皮肤温度在25°C和30°C水温下运动时略有升高，在35°C时显著升高。体重的损失随水温的升高而增加，表明运动时皮肤血流量和出汗量都随水温的升高而增加。体温的升高为运动过程中产生的热量的损失提供了温度调节驱动力。在35°C的水中运动时，心率增加最多，这很可能是由于对皮肤血流的需求增加。虽然在25°C的水温下，这种需求肯定是最小的，但在这个温度下的心率略高于30°C，这表明来自皮肤的冷信号反射激活了交感神经控制。与在25°C水中锻炼的受试者相比，在空气中跑步机上锻炼的受试者的平均皮肤和直肠温度显著增加。
Eight healthy and physically well-trained male students exercised on a treadmill for 60 min while being immersed in water to the middle of the chest in a laboratory flowmill. The water velocity was adjusted so that the intensity of exercise correspond to 50% maximal oxygen uptake of each subject, and experiments were performed once at each of three water temperatures: 25, 30, 35°C, following a 30-min control period in air at 25°C, and on a treadmill in air at an ambient temperature of 25°C. Thermal states during rest and exercise were determined by measuring rectal and skin temperatures at various points, and mean skin temperatures were calculated. The intensity of exercise was monitored by measuring oxygen consumption, and heart rate was monitored as an indicator for cardiovascular function. At each water temperature, identical oxygen consumption levels were attained during exercise, indicating that no extra heat was produced by shivering at the lowest water temperature. The slight rise in rectal temperature during exercise was not influenced by the water temperature. The temperatures of skin exposed to air rose slightly during exercise at 25°C and 30°C water temperature and markedly at 35°C. The loss of body mass increased with water temperature indicating that both skin blood flow and sweating during exercise increased with the rise in water temperature. The rise in body temperature provided the thermoregulatory drive for the loss of the heat generated during exercise. Heart rate increased most during exercise in water at 35°C, most likely due to enhanced requirements for skin blood flow. Although such requirements were certainly smallest at 25°C water temperature, heart rate at this temperature was slightly higher than at 30°C suggesting reflex activation of sympathetic control by cold signals from the skin. There was a significantly greater increase in mean skin and rectal temperatures in subjects exercising on the treadmill in air, compared to those exercising in water at 25°C.