TY - JOUR IS - 8 Y1 - 2022/02/13/ A1 - Racinais, Sebastien A1 - Havenith, George A1 - Aylwin, Polly A1 - Ihsan, Mohammed A1 - Taylor, Lee A1 - Adami, Paolo Emilio A1 - Adamuz, Maria-Carmen A1 - Alhammoud, Marine A1 - Alonso, Juan Manuel A1 - Bouscaren, Nicolas A1 - Buitrago, Sebastian A1 - Cardinale, Marco A1 - van Dyk, Nicol A1 - Esh, Chris J A1 - Gomez-Ezeiza, Josu A1 - Garrandes, Frederic A1 - Holtzhausen, Louis A1 - Labidi, Mariem A1 - Lange, Gunter A1 - Lloyd, Alexander A1 - Moussay, Sebastien A1 - Mtibaa, Khouloud A1 - Townsend, Nathan A1 - Wilson, Mathew G A1 - Bermon, Stephane PB - BMJ PUBLISHING GROUP N2 - Purpose To determine associations between thermal responses, medical events, performance, heat acclimation and health status during a World Athletics Championships in hot-humid conditions. Methods From 305 marathon and race-walk starters, 83 completed a preparticipation questionnaire on health and acclimation. Core (Tcore; ingestible pill) and skin (Tskin; thermal camera) temperatures were measured in-competition in 56 and 107 athletes, respectively. 70 in-race medical events were analysed retrospectively. Performance (% personal best) and did not finish (DNF) were extracted from official results. Results Peak Tcore during competition reached 39.6°C±0.6°C (maximum 41.1°C). Tskin decreased from 32.2°C±1.3°C to 31.0°C±1.4°C during the races (p<0.001). Tcore was not related to DNF (25% of starters) or medical events (p?0.150), whereas Tskin, Tskin rate of decrease and Tcore-to-Tskin gradient were (p?0.029). A third of the athletes reported symptoms in the 10 days preceding the event, mainly insomnia, diarrhoea and stomach pain, with diarrhoea (9% of athletes) increasing the risk of in-race medical events (71% vs 17%, p<0.001). Athletes (63%) who performed 5?30 days heat acclimation before the competition: ranked better (18±13 vs 28±13, p=0.009), displayed a lower peak Tcore (39.4°C±0.4°C vs 39.8°C±0.7°C, p=0.044) and larger in-race decrease in Tskin (?1.4°C±1.0°C vs ?0.9°C±1.2°C, p=0.060), than non-acclimated athletes. Although not significant, they also showed lower DNF (19% vs 30%, p=0.273) and medical events (19% vs 32%, p=0.179). Conclusion Tskin, Tskin rate of decrease and Tcore-to-Tskin gradient were important indicators of heat tolerance. While heat-acclimated athletes ranked better, recent diarrhoea represented a significant risk factor for DNF and in-race medical events. VL - 56 ID - discovery10169137 N1 - http://creativecommons.org/licenses/by-nc/4.0/ This is an open access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited, appropriate credit is given, any changes made indicated, and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/. SN - 0306-3674 JF - British Journal of Sports Medicine EP - 445 AV - public UR - http://dx.doi.org/10.1136/bjsports-2021-104569 SP - 439 TI - Association between thermal responses, medical events, performance, heat acclimation and health status in male and female elite athletes during the 2019 Doha World Athletics Championships KW - Science & Technology KW - Life Sciences & Biomedicine KW - Sport Sciences KW - exercise KW - hot temperature KW - EXERCISE KW - STRATEGIES KW - SYMPTOMS KW - COHORT KW - SEX ER -