Author(s): LEAL, D., GARRANDES, F., ADAMI, P.E., ESH, C.J., GALAN-LOPEZ, N., LEAL, D.V., GANDINI, S., LUCAS, R., STEVENS, C.J., TAYLOR, L., BERMON, S., Institution: UNIVERSITY OF MAIA, Country: PORTUGAL, Abstract-ID: 912

INTRODUCTION:
Elite endurance events increasingly take place in hot‑humid environments where thermal strain can impair performance and challenge athlete safety. Yet, the combined behavior of core (Tcore) and skin temperature (Tsk) during real‑world competition remains insufficiently described. The unique undulating course of the World Athletics Race-Walking Teams Championships Muscat 2022 allowed examination of how gradient‑related changes in speed influence thermoregulation. This study aimed to determine in‑race Tcore and Tsk responses of elite racewalkers competing under identical hot‑humid conditions.
METHODS:
Eleven men and nine women had Tcore (ingestible telemetry pill) and Tsk (skin‑contact thermistor) measured continuously during the 35 km race (17.5 laps of a 2 km course, 27 m elevation gain per lap). Environmental wet‑bulb globe temperature (WBGT) and relative humidity (RH) were recorded roadside.
RESULTS:
As sex did not modify any modelled effects (p > 0.200), data are presented pooled. WBGT and RH ranged from 21.6–28.6°C and 79–45% from start to finish. Tcore increased (p < 0.05) from 37.8 ± 0.6°C (36.1–38.7) to 39.1 ± 0.6°C (37.8–40.6). In contrast, Tsk decreased (p < 0.05) from 33.2 ± 1.4°C (31.5–36.5) to 30.3 ± 2.2°C (26.7–34.1). Course gradient affected Tsk (p < 0.001), which was higher during uphill (30.9 ± 1.9°C; 28.4–34.5) than downhill sections (30.1 ± 2.3°C; 27.2–34.4). Walking speed correlated with Tsk (Spearman’s rho = –0.141, p = 0.004) but not with Tcore (Pearson’s r = –0.257, p = 0.932).
CONCLUSION:
These results demonstrate that elite racewalkers tolerate substantial thermal strain during competition in hot‑humid environments, while Tsk is strongly influenced by airflow changes linked to speed and terrain. The interaction between course profile and heat dissipation highlights the importance of incorporating comprehensive heat‑acclimation strategies, alongside consideration of race layout, when preparing athletes for endurance events in challenging environmental conditions.