High Risk Of Heat-related Illnesses For Endurance Athletes During Athletics Championships In Hot Climate

Abstract

PURPOSE: To analyze the relationship between climatic conditions and the occurrence of heat-related illnesses during international athletics championships. METHODS: In this population-based study, all heat-related illnesses were selected from prospectively collected illness data from seven international outdoor World and European athletics championships between 2009 and 2018. The Universal Thermal Climate Index (UTCI) of each championship day was calculated as a model of thermoregulation for climatic conditions. The incidence rates of heat-related illnesses were analyzed in relation to the daily maximum UTCI temperature by fitting linear models. In addition, the relative risk (RR) was calculated for athletes from endurance and explosive disciplines, and for women and men. RESULTS: Overall, 132 heat-related illnesses occurred during the 50 championship days with UTCI temperatures between 15° and 37°Celsius (C). The average incidence rate of heat-related illness was 11.7 (95%CI 9.7 to 13.7) per 1000 registered athletes. The expected daily incidence rate of heat-related illness increased significantly with UTCI temperature (0.14 more illnesses per 1000 registered athletes per °C; 95%CI 0.10 to 0.18), doubling from 25 to 35 °C UTCI. No severe heat illness was observed below a UTCI temperature of 28 °C. Athletes in endurance disciplines had higher incidence rates than in explosive disciplines (RR = 21.7, 95% CI 12.0 to 39.2), while female and male athletes did not differ. CONCLUSION: More heat-related illness occurred on championship days with higher UTCI temperatures. There was a 20-fold increased risk in endurance disciplines compared with explosive disciplines. Strategies to prevent heat-related illness should focus on endurance disciplines in athletics competitions that occur in warm and humid climates with UTCI above 28 °C.