TY - JOUR T1 - 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 JF - British Journal of Sports Medicine JO - Br J Sports Med SP - 439 LP - 445 DO - 10.1136/bjsports-2021-104569 VL - 56 IS - 8 AU - Sebastien Racinais AU - George Havenith AU - Polly Aylwin AU - Mohammed Ihsan AU - Lee Taylor AU - Paolo Emilio Adami AU - Maria-Carmen Adamuz AU - Marine Alhammoud AU - Juan Manuel Alonso AU - Nicolas Bouscaren AU - Sebastian Buitrago AU - Marco Cardinale AU - Nicol van Dyk AU - Chris J Esh AU - Josu Gomez-Ezeiza AU - Frederic Garrandes AU - Louis Holtzhausen AU - Mariem Labidi AU - Gűnter Lange AU - Alexander Lloyd AU - Sebastien Moussay AU - Khouloud Mtibaa AU - Nathan Townsend AU - Mathew G Wilson AU - Stephane Bermon Y1 - 2022/04/01 UR - http://bjsm.bmj.com/content/56/8/439.abstract 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.Data are available on reasonable request. ER -