Sandström Marie E, Siegler Jason C, Lovell Ric J, Madden Leigh A, McNaughton Lars
Department of Sport, Health and Exercise Science, University of Hull, Cottingham Road, Hull, UK.
Cell Stress Chaperones. 2008 Summer;13(2):169-75. doi: 10.1007/s12192-008-0022-8. Epub 2008 Feb 19.
The purpose of this study was to investigate the alterations in serum heat shock protein (Hsp) 70 levels during a 15-consecutive-day intermittent heat-exercise protocol in a 29-year-old male ultra marathon runner. Heat acclimation, for the purpose of physical activities in elevated ambient temperatures, has numerous physiological benefits including mechanisms such as improved cardiac output, increased plasma volume and a decreased core temperature (T (c)). In addition to the central adaptations, the role of Hsp during heat acclimation has received an increasing amount of attention. The acclimation protocol applied was designed to correspond with the athlete's tapering period for the 2007 Marathon Des Sables. The subject (VO(2)max = 50.7 ml.kg(-1).min(-1), peak power output [PPO] = 376 W) cycled daily for 90 min at a workload corresponding to 50% of VO(2)max in a temperature-controlled room (average WBGT = 31.9 +/- 0.9 degrees C). Venous blood was sampled before and after each session for measurement of serum osmolality and serum Hsp70. In addition, T (c), heart rate (HR) and power output (PO) was measured throughout the 90 min to ensure that heat acclimation was achieved during the 15-day period. The results show that the subject was successfully heat acclimated as seen by the lowered HR at rest and during exercise, decreased resting and exercising T (c) and an increased PO. The heat exercise resulted in an initial increase in Hsp70 concentrations, known as thermotolerance, and the increase in Hsp70 after exercise was inversely correlated to the resting values of Hsp70 (Spearman's rank correlation = -0.81, p < 0.01). Furthermore, the 15-day heat-exercise protocol also increased the basal levels of Hsp70, a response different from that of thermotolerance. This is, as far as we are aware, the first report showing Hsp70 levels during consecutive days of intermittent heat exposure giving rise to heat acclimation. In conclusion, a relatively longer heat acclimation protocol is suggested to obtain maximum benefit of heat acclimation inclusive of both cellular and systemic adaptations.
本研究旨在调查一名29岁男性超级马拉松运动员在连续15天的间歇性热运动方案期间血清热休克蛋白（Hsp）70水平的变化。为了在环境温度升高时进行体育活动而进行的热适应具有许多生理益处，包括诸如改善心输出量、增加血浆量和降低核心温度（T（c））等机制。除了中枢适应性变化外，热适应过程中Hsp的作用也受到了越来越多的关注。所应用的适应方案旨在与该运动员2007年撒哈拉沙漠马拉松比赛的减量期相对应。该受试者（最大摄氧量[VO(2)max]=50.7 ml·kg(-1)·min(-1)，峰值功率输出[PPO]=376 W）在温度控制的房间（平均湿球黑球温度[WBGT]=31.9±0.9℃）中，每天以相当于VO(2)max 50%的工作量骑行90分钟。在每次训练前后采集静脉血，用于测量血清渗透压和血清Hsp70。此外，在整个90分钟内测量T（c）、心率（HR）和功率输出（PO），以确保在15天内实现热适应。结果表明，从静息和运动时HR降低、静息和运动时T（c）降低以及PO增加可以看出，该受试者成功实现了热适应。热运动导致Hsp70浓度最初升高，即产生热耐受性，且运动后Hsp70的升高与Hsp70的静息值呈负相关（斯皮尔曼等级相关=-0.81，p<0.01）。此外，为期15天的热运动方案还提高了Hsp70的基础水平，这一反应与热耐受性不同。据我们所知，这是第一份显示连续数天间歇性热暴露期间Hsp70水平导致热适应的报告。总之，建议采用相对较长的热适应方案，以获得热适应的最大益处，包括细胞和全身适应性变化。
