Thermoregulatory responses during road races in hot-humid conditions at the 2019 Athletics World Championships
Purpose: To characterise thermoregulatory and performance responses of elite road-race athletes, while competing in hot, humid, night-time conditions during the 2019 IAAF World Athletic Championships.
Method: Male and female athletes, competing in the 20 km racewalk (n=20 males, 24 females), 50 km racewalk (n=19 males, 8 females) and marathon (n=15 males, 22 females) participated. Exposed mean skin (Tsk) and continuous core body (Tc) temperature were recorded with infrared thermography and ingestible telemetry pill, respectively.
Results: The range of ambient conditions (recorded roadside) were 29.3-32.7°C air temperature, 46-81 % relative humidity, 0.1-1.7 m∙s-1 air velocity and 23.5-30.6°C wet bulb globe temperature. Tc increased by 1.5 ± 0.1°C but mean Tsk decreased by 1.5 ± 0.4°C over the duration of the races. Tsk and Tc changed most rapidly at the start of the races and then plateaued, with Tc showing a rapid increase again at the end, in a pattern mirroring pacing. Performance times were between 3 to 20 % (mean = 113 ± 6%) longer during the championships compared to the personal best (PB) of athletes. Overall mean performance relative to PB was correlated with the wet-bulb globe temperature (WBGT) of each race (R2 = 0.89), but not with thermophysiological variables (R2 ≤ 0.3).
Conclusion: As previously reported in exercise heat stress, in this field study Tc rose with exercise duration, whereas Tsk showed a decline. The latter contradicts the commonly recorded rise and plateau in laboratory studies at similar ambient temperatures, but without realistic air movement.
World Athletic (formerly IAAF)
- Design and Creative Arts
- Sport, Exercise and Health Sciences
Published inJournal of Applied Physiology
PublisherAmerican Physiological Society
- VoR (Version of Record)
Rights holder© The Authors
Publisher statementThis is an Open Access Article. It is published by the American Physiological Society under the Creative Commons Attribution 4.0 International Licence (CC BY). Full details of this licence are available at: https://creativecommons.org/licenses/by/4.0/