Hydration and cooling in elite athletes: relationship with performance, body mass loss and body temperatures during the Doha 2019 IAAF World Athletics Championships.

Affiliation

Racinais S(1), Ihsan M(2)(3), Taylor L(4)(5), Cardinale M(2)(6), Adami PE(7), Alonso JM(8), Bouscaren N(9), Buitrago S(10), Esh CJ(2)(4), Gomez-Ezeiza J(11), Garrandes F(7), Havenith G(12), Labidi M(2), Lange G(7), Lloyd A(12), Moussay S(13), Mtibaa K(14), Townsend N(2)(15), Wilson MG(2)(6), Bermon S(7)(16).
Author information:
(1)Research and Scientific Support, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Ad Dawhah, Qatar [Email]
(2)Research and Scientific Support, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Ad Dawhah, Qatar.
(3)Human Potential Translational Research Program, NUS Yong Loo Lin School of Medicine, Singapore.
(4)School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK.
(5)Human Performance Research Centre, University of Technology Sydney, Sydney, New South Wales, Australia.
(6)Institute of Sport Exercise and Health
(ISEH), University College London, London, UK.
(7)Health and Science Department, World Athletics, Monaco.
(8)Sports Medicine, Aspetar Orthopaedic and Sports Medicine Hospital, Doha, Ad Dawhah, Qatar.
(9)Inserm CIC1410, CHU Reunion, La Réunion, France.
(10)Olympic Training and Service Centre Lower Saxony, Hannover, Germany.
(11)Institute of Sport and Exercise Medicine, Stellenbosch University Faculty of Medicine and Health Sciences, Cape Town, Western Cape, South Africa.
(12)Environmental Ergonomics Research Centre, Loughborough University, Loughborough, Leics, UK.
(13)Normandie Univ, UNICAEN, INSERM, COMETE, CYCERON, CHU Caen, Caen, Normandie, France.
(14)Physical Education Department, College of Education, Qatar University, Doha, Qatar.
(15)College of Health and Life Sciences, Hamad Bin Khalifa University, Doha, Ad Dawhah, Qatar.
(16)Human Motricity Laboratory Expertise Sport Health, Cote d'Azur University, Nice, Provence-Alpes-Côte d'Azu, France.

Abstract

PURPOSE: To characterise hydration, cooling, body mass loss, and core (Tcore) and skin (Tsk) temperatures during World Athletics Championships in hot-humid conditions. METHODS: Marathon and race-walk (20 km and 50 km) athletes (n=83, 36 women) completed a pre-race questionnaire. Pre-race and post-race body weight (n=74), Tcore (n=56) and Tsk (n=49; thermography) were measured. RESULTS: Most athletes (93%) had a pre-planned drinking strategy (electrolytes (83%), carbohydrates (81%)) while ice slurry was less common (11%; p<0.001). More men than women relied on electrolytes and carbohydrates (91%-93% vs 67%-72%, p≤0.029). Drinking strategies were based on personal experience (91%) rather than external sources (p<0.001). Most athletes (80%) planned pre-cooling (ice vests (53%), cold towels (45%), neck collars (21%) and ice slurry (21%)) and/or mid-cooling (93%; head/face dousing (65%) and cold water ingestion (52%)). Menthol usage was negligible (1%-2%). Pre-race Tcore was lower in athletes using ice vests (37.5°C±0.4°C vs 37.8°C±0.3°C, p=0.024). Tcore (pre-race 37.7°C±0.3°C, post-race 39.6°C±0.6°C) was independent of event, ranking or performance (p≥0.225). Pre-race Tsk was correlated with faster race completion (r=0.32, p=0.046) and was higher in non-finishers (did not finish (DNF); 33.8°C±0.9°C vs 32.6°C±1.4°C, p=0.017). Body mass loss was higher in men than women (-2.8±1.5% vs -1.3±1.6%, p<0.001), although not associated with performance. CONCLUSION: Most athletes' hydration strategies were pre-planned based on personal experience. Ice vests were the most adopted pre-cooling strategy and the only one minimising Tcore, suggesting that event organisers should be cognisant of logistics (ie, freezers). Dehydration was moderate and unrelated to performance. Pre-race Tsk was related to performance and DNF, suggesting that Tsk modulation should be incorporated into pre-race strategies.