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