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

Abstract

PurposeTo determine associations between thermal responses, medical events, performance, heat acclimation and health status during a World Athletics Championships in hot-humid conditions.MethodsFrom 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.ResultsPeak 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).ConclusionTskin, 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.

IOC consensus statement on recommendations and regulations for sport events in the heat

“…While there is a multitude of mitigation strategies that can effectively reduce the risk of one's vulnerability to exercise heat stress (eg, acclimation), implementation of these strategies remains insufficient in sport settings. 13 In addition, as sport events continue to be held in extreme heat, we must ensure that evidence-based treatment of EHS is implemented to maximise survival from this potentially lethal medical condition. 14 This document presents the consensus recommendations from the panel of experts and stakeholders convened by the IOC Medical and Scientific Commission to protect athletes competing in the heat.…”

“…Of the cohort of athletes exposed to similar hot conditions during a given event, only a minority will require medical support. 13 While there is interindividual variability in both the acute responses to heat and heat acclimation kinetics, all athletes can and should adapt and prepare for the heat. [62][63][64] There is also a growing evidence showing that the recent health status of the athlete (especially if the athlete is experiencing diarrhoea) is a major risk factor for an adverse medical outcome when competing in the heat.…”

“…Transfer from the finish line to the medical station is generally managed by wheelchair with recent data suggesting that endurance event organisers should plan 1 wheelchair per five competitors for elite international athletic events in hot and humid conditions. 13 Recommendations ► Water, ice bag and ice towels should be available to all athletes at the finish line. ► Depending on the proximity of the medical venue from the finish line and the existence of a pathway to allow the reutilisation of the wheelchairs, a demand of up to 1 wheelchair per five competitors may be considered for elite international athletic events in hot and humid conditions.…”

“…Unfortunately, the level of environmental heat stress experienced by elite athletes will continue to rise in the coming years due to a combination of the increased prevalence, intensity and duration of bouts of extremely hot weather (ie, heat waves) that are occurring due to climate change and sport globalisation leading to more competitions being organised in extremely hot climates. While there is a multitude of mitigation strategies that can effectively reduce the risk of one’s vulnerability to exercise heat stress (eg, acclimation), implementation of these strategies remains insufficient in sport settings 13. In addition, as sport events continue to be held in extreme heat, we must ensure that evidence-based treatment of EHS is implemented to maximise survival from this potentially lethal medical condition 14…”

New Advances in Human Thermophysiology

“…However, certain conditions may not always be compensable either due to exercise intensity, individual characteristics or/and extreme environmental conditions. In this sense, although these complicated scenarios are of great interest in recent years, helping us to assess impact and prevention strategies for high-level athletes during events such as the Olympic Games Tokyo [ 4 ], the Doha World Athletics Championships [ 5 ] or the Soccer World Cup in Qatar [ 6 ], human thermophysiology is present in diverse applications (e.g., occupational ergonomics).…”