Stephenson Lou A, Vernieuw Carrie R, Leammukda Walida, Kolka Margaret A
U.S. Army Research Institute of Environmental Medicine, Thermal and Mountain Medicine, Natick, MA 01760, USA.
Aviat Space Environ Med. 2007 Apr;78(4):377-82.
A novel pulsed cooling paradigm (PCskin) integrating mean skin temperature (Tsk) feedback was compared with constant cooling (CC) or time-activated pulsed cooling (PC).
Eight males exercised while wearing personal protective equipment (PPE) in a warm, dry environment (dry bulb temperature: 30 degrees C; dew-point temperature: 11 degrees C) in each of the tests. Treadmill exercise was performed (approximately 225 W x m(-2)) for 80 min. A liquid cooling garment (LCG) covered 72% of the body surface area. Core temperature (Tc), local skin temperatures, heart rate, inlet and outlet LCG perfusate temperatures, flow, and electrical power to the LCG and metabolic rate were measured during exercise.
At 75 min of exercise Tsk was higher (33.9 +/- 0.2 degrees C) in PCskin, than in PC (33.1 +/- 0.5 degrees C) or CC (32.0 +/- 0.6 degrees C) and PC > CC. The changes in Tc and heart rate during the tests were not different. Tc at 75 min was not different among the cooling paradigms (37.6 +/- 0.3 degrees C in PCskin, 37.6 +/- 0.2 degrees C in PC and 37.6 +/- 0.2 degrees C in CC). Heart rate averaged 124 +/- 10 bpm in PCskin, 120 +/- 9 bpm in PC and 117 +/- 9 bpm in CC. Total body insulation (degrees C x W(-1) x m(-2)) was significantly reduced in PCskin (0.020 +/- 0.003) and PC (0.024 +/- 0.004) from CC (0.029 +/- 0.004). Electrical power in PCskin was reduced by 46% from CC and by 28% from PC.
DISCUSSION/CONCLUSION: Real-time Tsk feedback to control cooling optimized LCG efficacy and reduced electrical power for cooling without significantly changing cardiovascular strain in exercising men wearing PPE.
将整合平均皮肤温度（Tsk）反馈的新型脉冲冷却模式（PCskin）与持续冷却（CC）或定时激活脉冲冷却（PC）进行比较。
在每次测试中，八名男性在温暖干燥的环境（干球温度：30摄氏度；露点温度：11摄氏度）中穿着个人防护装备（PPE）进行运动。进行跑步机运动（约225 W·m⁻²）80分钟。一件液体冷却服（LCG）覆盖72%的身体表面积。在运动期间测量核心温度（Tc）、局部皮肤温度、心率、LCG灌注液的进出口温度、流量、LCG的电功率以及代谢率。
在运动75分钟时，PCskin组的Tsk（33.9±0.2摄氏度）高于PC组（33.1±0.5摄氏度）或CC组（32.0±0.6摄氏度），且PC组＞CC组。测试期间Tc和心率的变化无差异。在75分钟时，各冷却模式下的Tc无差异（PCskin组为37.6±0.3摄氏度，PC组为37.6±0.2摄氏度，CC组为37.6±0.2摄氏度）。PCskin组的平均心率为124±10次/分钟，PC组为120±9次/分钟，CC组为117±9次/分钟。与CC组（0.029±0.004）相比，PCskin组（0.020±0.003）和PC组（0.024±0.004）的全身隔热（摄氏度·瓦⁻¹·米⁻²）显著降低。PCskin组的电功率比CC组降低了46%，比PC组降低了28%。
讨论/结论：通过实时Tsk反馈来控制冷却，可优化LCG的功效并降低冷却所需的电功率，同时在穿着PPE进行运动的男性中不会显著改变心血管压力。
