Convit Lilia, Périard Julien D, Carr Amelia J, Warmington Stuart, Motiyani Gunjit, Orellana Liliana, Snipe Rhiannon M J
Centre for Sport Research, School of Exercise and Nutrition Sciences, Deakin University, Burwood, Victoria, Australia.
Research Institute for Sport and Exercise, University of Canberra, Canberra, Bruce, Australian Capital Territory, Australia.
Temperature (Austin). 2025 Feb 22;12(2):133-148. doi: 10.1080/23328940.2025.2465023. eCollection 2025.
This study investigated the effect of mixed pre-cooling (cooling vest and ice-slurry) on thermal and cardiovascular strain and performance in unacclimatized females exercising in the heat during menstrual cycle (MC) Phase-1 (low estrogen and progesterone) and Phase-4 (moderate estrogen and high progesterone). In a randomized crossover design, 11 runners completed two trials in each MC Phase: mixed pre-cooling (wearing a cooling vest around the torso for 30 min and ingesting 7.5 g.kg of body mass of ice slurry), and control (equivalent slurry volume at ~20°C without a cooling vest), prior to a 10-km running time trial (TT) in 34°C and 60% relative humidity. Rectal temperature (T), heart rate (HR), and perceptual responses were measured throughout the TT. Linear mixed models were fitted to estimate intervention and MC phase effects. Mixed pre-cooling had no effect on HR (1.06 [-0.83, 2.95] beats.min; = 0.272) or TT completion time (-0.23 [-1.32, 0.86] min; = 0.677) versus control. T (-0.21 [-0.34, -0.07] °C; = 0.003) and thermal sensation (-0.61 [-0.78, -0.44] au; < 0.001) were significantly lower with mixed pre-cooling compared to control. Rise in T (-0.1 [-0.3, 0.0] °C) and thermal sensation were attenuated in MC phase-4 (-0.57 [-0.81, -0.34] au; all < 0.05). Mixed pre-cooling was effective at attenuating the rise in T for a similar work rate, particularly in MC phase-4, where females may experience greater heat thermosensation. However, the magnitude of attenuated T does not improve 10-km running performance in the heat, suggesting additional cooling and/or heat mitigation strategies may be required to improve performance.
本研究调查了混合预冷（冷却背心和冰浆）对未适应环境的女性在月经周期（MC）第1阶段（低雌激素和孕酮）和第4阶段（中等雌激素和高孕酮）于炎热环境中运动时的热应激和心血管应激以及运动表现的影响。在随机交叉设计中，11名跑步者在每个MC阶段完成两项试验：混合预冷（在躯干周围穿着冷却背心30分钟并摄入每千克体重7.5克的冰浆）和对照（摄入约20°C的等量浆体但不穿冷却背心），然后在34°C和60%相对湿度下进行10公里跑步计时赛（TT）。在整个TT过程中测量直肠温度（T）、心率（HR）和感知反应。采用线性混合模型来估计干预和MC阶段的影响。与对照相比，混合预冷对HR（1.06[-0.83,2.95]次/分钟；P = 0.272）或TT完成时间（-0.23[-1.32,0.86]分钟；P = 0.677）没有影响。与对照相比，混合预冷时T（-0.21[-0.34,-0.07]°C；P = 0.003）和热感觉（-0.61[-0.78,-0.44]au；P < 0.001）显著更低。在MC第4阶段，T的升高（-0.1[-0.3,0.0]°C）和热感觉有所减弱（-0.57[-0.81,-0.34]au；所有P < 0.05）。在相同工作强度下，混合预冷有效地减弱了T的升高，尤其是在MC第4阶段，此时女性可能会经历更强的热感觉。然而，T减弱的幅度并未改善在炎热环境中的10公里跑步表现，这表明可能需要额外的冷却和/或热缓解策略来提高表现。
