Young A J, Castellani J W, O'Brien C, Shippee R L, Tikuisis P, Meyer L G, Blanchard L A, Kain J E, Cadarette B S, Sawka M N
United States Army Research Institute of Environmental Medicine, Natick, Massachusetts 01760, USA.
J Appl Physiol (1985). 1998 Oct;85(4):1210-7. doi: 10.1152/jappl.1998.85.4.1210.
The purpose of this study was to determine how chronic exertional fatigue and sleep deprivation coupled with negative energy balance affect thermoregulation during cold exposure. Eight men wearing only shorts and socks sat quietly during 4-h cold air exposure (10 degreesC) immediately after (<2 h, A) they completed 61 days of strenuous military training (energy expenditure approximately 4,150 kcal/day, energy intake approximately 3,300 kcal/day, sleep approximately 4 h/day) and again after short (48 h, SR) and long (109 days, LR) recovery. Body weight decreased 7.4 kg from before training to A, then increased 6.4 kg by SR, with an additional 6.4 kg increase by LR. Body fat averaged 12% during A and SR and increased to 21% during LR. Rectal temperature (Tre) was lower before and during cold air exposure for A than for SR and LR. Tre declined during cold exposure in A and SR but not LR. Mean weighted skin temperature (Tsk) during cold exposure was higher in A and SR than in LR. Metabolic rate increased during all cold exposures, but it was lower during A and LR than SR. The mean body temperature (0.67 Tre + 0.33 Tsk) threshold for increasing metabolism was lower during A than SR and LR. Thus chronic exertional fatigue and sleep loss, combined with underfeeding, reduced tissue insulation and blunted metabolic heat production, which compromised maintenance of body temperature. A short period of rest, sleep, and refeeding restored the thermogenic response to cold, but thermal balance in the cold remained compromised until after several weeks of recovery when tissue insulation had been restored.
本研究的目的是确定慢性运动性疲劳、睡眠剥夺以及负能量平衡相结合如何影响冷暴露期间的体温调节。八名仅穿着短裤和袜子的男性，在完成61天高强度军事训练后（<2小时，A组）立即进行4小时的冷空气暴露（10摄氏度），训练期间能量消耗约4150千卡/天，能量摄入约3300千卡/天，睡眠约4小时/天；在短期（48小时，SR组）和长期（109天，LR组）恢复后再次进行冷空气暴露。从训练前到A组，体重下降了7.4千克，到SR组体重增加了6.4千克，到LR组又额外增加了6.4千克。A组和SR组期间体脂平均为12%，LR组增加到21%。A组在冷空气暴露前和暴露期间的直肠温度（Tre）低于SR组和LR组。A组和SR组在冷暴露期间Tre下降，LR组则未下降。冷暴露期间A组和SR组的平均加权皮肤温度（Tsk）高于LR组。所有冷暴露期间代谢率均增加，但A组和LR组低于SR组。A组增加代谢的平均体温（0.67Tre + 0.33Tsk）阈值低于SR组和LR组。因此，慢性运动性疲劳、睡眠不足以及进食不足相结合，降低了组织隔热性并减弱了代谢产热，这损害了体温的维持。短时间的休息、睡眠和重新进食恢复了对寒冷的产热反应，但在组织隔热性恢复的数周恢复之前，寒冷中的热平衡仍然受到损害。
