Wilson Thad E, Johnson Stephen C, Petajan Jack H, Davis Scott L, Gappmaier Eduard, Luetkemeier Maurie J, White Andrea T
Department of Exercise and Sport Science, College of Health and School of Medicine, 250 S 1850 E, Rm 241, University of Utah, Salt Lake City, UT 84112, USA.
Eur J Appl Physiol. 2002 Nov;88(1-2):67-75. doi: 10.1007/s00421-002-0696-z. Epub 2002 Aug 24.
This study compared the effects of pre-exercise cooling with control water immersions on exercise-induced thermal loads derived from steady-state submaximal exercise. Eight healthy male participants [mean (SEM) age 29 (1) years, maximal oxygen uptake 3.81 (0.74) l x min(-1), and body surface area 1.85 (0.11) m(2)] took part in experiments that included 30 min of baseline data collection [ambient temperature 21.3 (0.2 degrees C)], 30 min of immersion in water to the level of the supra-iliac crest [water temperatures of 35.1 (0.3) degrees C for thermoneutral and 17.7 (0.5) degrees C for precooled treatments], and 60 min of cycling exercise at 60% of maximal oxygen uptake. No significant differences were noted during exercise in net mechanical efficiency, metabolic rate, O(2) pulse, or ratings of perceived exertion between the two treatments. Precooling resulted in a significant negative body heat storage during immersion and allowed greater heat storage during exercise. However, net body heat storage for the entire protocol was no different between treatments. Cooling significantly lowered rectal, mean skin, and mean body temperatures as well as more than doubling the exercise time until a 0.5 degrees C rectal temperature increase was observed. The cooling trial significantly delayed onset of sweating by 19.62 min and decreased sweat rate by 255 ml x h(-1) compared to control. Thermal and sweat sensation scores were lower after the cooling treatment compared to control. These data suggest that lower-body precooling is effective at decreasing body heat storage prior to exercise and decreases reliance on heat dissipation mechanisms during exercise. Therefore, this unique, well-tolerated cooling treatment should have a broader application than other precooling treatments.
本研究比较了运动前进行冷却处理与对照水浸处理对稳态次最大运动所产生的运动性热负荷的影响。八名健康男性参与者[平均（标准误）年龄29（1）岁，最大摄氧量3.81（0.74）升/分钟，体表面积1.85（0.11）平方米]参与了实验，实验包括30分钟的基线数据收集[环境温度21.3（0.2）摄氏度]、30分钟的水浸至髂嵴水平[热中性水温为35.1（0.3）摄氏度，预冷处理水温为17.7（0.5）摄氏度]以及60分钟的以最大摄氧量60%进行的骑行运动。在运动过程中，两种处理在净机械效率、代谢率、氧脉搏或主观用力感觉评分方面均未观察到显著差异。预冷导致在水浸期间身体热量储存显著为负，并使运动期间能够储存更多热量。然而，两种处理在整个实验方案中的净身体热量储存并无差异。冷却显著降低了直肠温度、平均皮肤温度和平均体温，并且在观察到直肠温度升高0.5摄氏度之前，运动时间增加了一倍多。与对照相比，冷却试验使出汗开始时间显著延迟了19.62分钟，并使出汗率降低了255毫升/小时。与对照相比，冷却处理后的热感觉和出汗感觉评分更低。这些数据表明，下半身预冷在运动前有效减少身体热量储存，并减少运动期间对散热机制的依赖。因此，这种独特的、耐受性良好的冷却处理应比其他预冷处理具有更广泛的应用。
