Institute of Exercise Biology and Physiotherapy, Estonian Centre of Behavioural and Health Sciences, University of Tartu, 18 Ülikooli Street, Tartu, Estonia.
Eur J Appl Physiol. 2012 Dec;112(12):4091-101. doi: 10.1007/s00421-012-2371-3. Epub 2012 Mar 13.
We examined the effect of heat acclimation (HA) on endurance capacity and blood prolactin (PRL) response to moderate intensity exercise in the heat in young male subjects (n = 21). Three exercise tests (ET) were completed on a treadmill: H1 (walk at 60% VO(2)peak until exhaustion at 42°C), N (walk at 22°C; duration equal to H1) and H2 (walk until exhaustion at 42°C after a 10-day HA program). Heart rate (HR), skin (T (sk)) and core (T (c)) temperatures and body heat storage (HS) were measured. Blood samples were taken immediately before, during and immediately after each ET. HA resulted in lower HR, T (sk), T (c) and HS rate (P < 0.05) during ET, whereas endurance capacity increased from 88.6 ± 27.5 min in H1 to 162.0 ± 47.8 min in H2 (P < 0.001). Blood PRL concentration was lower (P < 0.05) during exercise in H2 compared to H1 but the peak PRL level observed at the time of exhaustion did not differ in the two trials. Blood PRL concentration at 60 min of exercise in H1 correlated with time to exhaustion in H1 (r = -0.497, P = 0.020) and H2 (r = -0.528, P = 0.014). In conclusion, HA slows down the increase in blood PRL concentration but does not reduce the peak PRL level occurring at the end of exhausting endurance exercise in the heat. Blood PRL response to exercise in the heat in non-heat-acclimated subjects is associated with their endurance capacity in the heat in a heat-acclimated state.
我们研究了热适应（HA）对年轻男性受试者在热环境中进行中等强度运动的耐力能力和血液催乳素（PRL）反应的影响（n=21）。在跑步机上完成了三项运动测试（ET）：H1（以 60% VO2peak 行走，直到在 42°C 时衰竭）、N（在 22°C 行走；持续时间与 H1 相同）和 H2（在 10 天的 HA 程序后在 42°C 行走直至衰竭）。测量心率（HR）、皮肤（T（sk））和核心（T（c））温度和体热储存（HS）。在每次 ET 之前、期间和之后立即采集血液样本。HA 导致 ET 期间 HR、T（sk）、T（c）和 HS 率降低（P<0.05），而耐力能力从 H1 中的 88.6±27.5 分钟增加到 H2 中的 162.0±47.8 分钟（P<0.001）。与 H1 相比，H2 运动期间的血液 PRL 浓度较低（P<0.05），但两次试验中衰竭时观察到的 PRL 峰值水平没有差异。H1 运动 60 分钟时的血液 PRL 浓度与 H1 （r=-0.497，P=0.020）和 H2 （r=-0.528，P=0.014）的衰竭时间相关。总之，HA 会减缓血液 PRL 浓度的增加，但不会降低热衰竭运动结束时发生的 PRL 峰值水平。非热适应受试者在热环境中运动时的 PRL 反应与他们在热适应状态下在热环境中的耐力能力相关。
