Périard Julien D, Wilson Mathew G, Tebeck Samuel T, Gilmore James B, Stanley Jamie, Girard Olivier
Research Institute for Sport and Exercise, University of Canberra, Canberra, ACT, AUSTRALIA.
School of Human Sciences (Exercise and Sport Science), University of Western Australia, Crawley, WA, AUSTRALIA.
Med Sci Sports Exerc. 2023 Jan 1;55(1):32-45. doi: 10.1249/MSS.0000000000003028. Epub 2022 Aug 16.
This study aimed to characterize the thermal and cardiovascular strain of professional cyclists during the 2019 Tour Down Under and determine the associations between thermal indices and power output, and physiological strain.
Gastrointestinal temperature ( Tgi ), heart rate (HR), and power output were recorded during the six stages (129-151.5 km) of the Tour Down Under in ≤22 male participants. Thermal indices included dry-bulb, black-globe, wet-bulb, and wet-bulb-globe (WBGT) temperature; relative humidity (RH), Heat Index; Humidex; and universal thermal climate index. The heat stress index (HSI), which reflects human heat strain, was also calculated.
Dry-bulb temperature was 23°C-37°C, and RH was 18%-72% (WBGT: 21°C-29°C). Mean Tgi was 38.2°C-38.5°C, and mean peak Tgi was 38.9°C-39.4°C, both highest values recorded during stage 3 (WBGT: 27°C). Peak individual Tgi was ≥40.0°C in three stages and ≥39.5°C in 14%-33% of cyclists in five stages. Mean HR was 131-147 bpm (68%-77% of peak), with the highest mean recorded in stage 3 ( P ≤ 0.005). Mean power output was 180-249 W, with the highest mean recorded during stage 4 ( P < 0.001; 21°C WBGT). The thermal indices most strongly correlated with power output were black-globe temperature ( r = -0.778), RH ( r = 0.768), universal thermal climate index ( r = -0.762), and WBGT ( r = -0.745; all P < 0.001). Mean Tgi was correlated with wet-bulb temperature ( r = 0.495), HSI ( r = 0.464), and Humidex ( r = 0.314; all P < 0.05), whereas mean HR was most strongly correlated with HSI ( r = 0.720), along with Tgi ( r = 0.599) and power output ( r = 0.539; all P < 0.05).
Peak Tgi reached 40.0°C in some cyclists, although most remained <39.5°C with an HR of ~73% of peak. Power output was correlated with several thermal indices, primarily influenced by temperature, whereas Tgi and HR were associated with the HSI, which has potential for sport-specific heat policy development.
本研究旨在描述2019年环澳自行车赛期间职业自行车运动员的热应激和心血管应激情况，并确定热指数与功率输出及生理应激之间的关联。
在环澳自行车赛的六个赛段（129 - 151.5千米）中，对≤22名男性参与者记录其胃肠道温度（Tgi）、心率（HR）和功率输出。热指数包括干球温度、黑球温度、湿球温度和湿球黑球温度（WBGT）；相对湿度（RH）、热指数；湿度指数；以及通用热气候指数。还计算了反映人体热应激的热应激指数（HSI）。
干球温度为23°C - 37°C，RH为18% - 72%（WBGT：21°C - 29°C）。平均Tgi为38.2°C - 38.5°C，平均峰值Tgi为38.9°C - 39.4°C，均为第3赛段记录到的最高值（WBGT：27°C）。在三个赛段中，个体峰值Tgi≥40.0°C，在五个赛段中，14% - 33%的自行车运动员峰值Tgi≥39.5°C。平均HR为131 - 147次/分钟（峰值的68% - 77%），第3赛段记录到的平均HR最高（P≤0.005）。平均功率输出为180 - 249瓦，第4赛段记录到的平均功率输出最高（P < 0.001；WBGT为21°C）。与功率输出相关性最强的热指数是黑球温度（r = -0.778）、RH（r = 0.768）、通用热气候指数（r = -0.762）和WBGT（r = -0.745；均P < 0.001）。平均Tgi与湿球温度（r = 0.495）、HSI（r = 0.464）和湿度指数（r = 0.314；均P < 0.05）相关，而平均HR与HSI相关性最强（r = 0.720），同时与Tgi（r = 0.599）和功率输出（r = 0.539；均P < 0.05）相关。
部分自行车运动员的峰值Tgi达到40.0°C，不过大多数仍<39.5°C，心率约为峰值的73%。功率输出与多个热指数相关，主要受温度影响，而Tgi和HR与HSI相关，这为制定特定运动项目的热政策提供了可能。
