Renaghan Eric, Wishon Michael J, Wittels Harrison L, Hecocks Dustin, Galasso Peter J, Ren Tom, McDonald Samantha M, Feigenbaum Luis A, Wittels S H
Department of Athletics, Sports Science, University of Miami, Miami, FL.
Tiger Tech Solutions, Inc., Miami, FL.
Med Sci Sports Exerc. 2025 Feb 25;57(7):1481-7. doi: 10.1249/MSS.0000000000003686.
Cooling interventions mitigating heat-related declines in autonomic nervous system (ANS) function are understudied in American football.
This study exposed fifty, collegiate male athletes during their 2023 season to two bouts of cold air via air-conditioning prior to (60 mins) and during (5 min) training sessions in a hot and humid climate. Armband monitors, (Warfighter MonitorTM, Tiger Tech Solutions, Inc., Miami, FL, USA), were used to continuously measure core temperature (°C) during training and baseline heart rate (HR), HR recovery and HR variability (HRV) 24 hours post training. Two HRV time-domain indices were estimated: root mean square of the standard deviation of the NN interval (rMSSD) and the standard deviation of the NN interval (SDNN). These data (2023) were then compared to data collected throughout the previous season (2022) during which players were not provided a cold-air intervention. As such, the 2022 cohort served as a "control" group.
Linear regression models no statistically significant associations at the following core temperature thresholds: ≥ 37.0 °C (baseline HR: p = 0.74; HR recovery: p = 0.71, rMSSD: p = 0.74; SDNN: p = 0.78), ≥ 38.0 °C baseline HR: p = 0.74; HR Recovery: p = 0.74; rMSSD: p = 0.68 and SDNN: p = 0.89) and ≥ 39.0 °C: baseline HR: p = 0.75; HR Recovery: p = 0.82; rMSSD: p = 0.78 and SDNN: p = 0.83). Compared to the 2022 season, the athletes spent considerably less time training under the higher core temperature thresholds (≥ 38 °C: 19.5 min vs 9.7 min; ≥ 39 °C: 10.5 min vs 0.9 min), respectively, despite longer overall training duration, (161.1 min vs 187.4 min).
Our findings suggest that incorporating bouts of cold air exposure when training in high heat and humidity may mitigate the established heat-related deterioration in ANS function.
在美式橄榄球运动中，对于减轻与热相关的自主神经系统（ANS）功能下降的降温干预措施的研究较少。
本研究让50名大学男子运动员在2023赛季期间，于炎热潮湿气候下的训练前（60分钟）和训练期间（5分钟）通过空调接受两回合冷空气吹拂。使用臂带监测器（Warfighter MonitorTM，Tiger Tech Solutions公司，美国佛罗里达州迈阿密）在训练期间持续测量核心温度（摄氏度），并在训练后24小时测量基线心率（HR）、心率恢复情况和心率变异性（HRV）。估计了两个HRV时域指标：NN间期标准差的均方根（rMSSD）和NN间期的标准差（SDNN）。然后将这些数据（2023年）与上一赛季（2022年）收集的数据进行比较，上一赛季球员未接受冷空气干预。因此，2022年的队列作为“对照组”。
线性回归模型在以下核心温度阈值下无统计学显著关联：≥37.0°C（基线HR：p = 0.74；心率恢复：p = 0.71，rMSSD：p = 0.74；SDNN：p = 0.78）、≥38.0°C（基线HR：p = 0.74；心率恢复：p = 0.74；rMSSD：p = 0.68；SDNN：p = 0.89）和≥39.0°C（基线HR：p = 0.75；心率恢复：p = 0.82；rMSSD：p = 0.78；SDNN：p = 0.83）。与2022赛季相比，尽管总体训练时长更长（161.1分钟对187.4分钟），但运动员在较高核心温度阈值（≥38°C：19.5分钟对9.7分钟；≥39°C：10.5分钟对0.9分钟）下训练的时间显著减少。
我们的研究结果表明，在高温高湿环境下训练时加入冷空气吹拂回合，可能会减轻已确定的与热相关的ANS功能恶化。
