ECSS Paris 2023: OP-PN22
INTRODUCTION: Heat training (HT; acclimation and acclimatisation) is considered essential for preparing athletes for competition in hot environments. Although laboratory research has informed evidence-based HT guidelines, little is known about how these guidelines are applied in high‑performance settings. This study described current perceptions, considerations, and prescription approaches of practitioners in high‑performance sport. METHODS: Practitioners supporting national- to world-class athletes preparing for competition in hot environments completed an online questionnaire assessing demographics, perceptions, planning considerations, barriers, and HT protocol characteristics. Data is presented as percentages or median (interquartile range [IQR]). RESULTS: Fifty-one practitioners responded, primarily sports scientists/physiologists (72%), based in Europe (45%) and Oceania (23%). Most (73%) had ≥5 years’ experience prescribing HT, 69% had experience with both heat acclimation and acclimatisation, and 73% primarily supported endurance‑based athletes in preparation for competition in hot environments (e.g. Triathlon: 29% and Cycling: 24%). Practitioners reported prescribing HT mainly to induce adaptations (31%) and to familiarise athletes with the expected environmental demands (26%). Nearly all practitioners (96%) considered HT of high importance for competition in hot conditions, whereas only 14% considered HT of high importance for cool conditions. The athlete‑ and competition‑based considerations of high importance for HT were training‑cycle phase/load (73%) and expected competition conditions (94%), respectively. The most common barriers were interference with training (27%) and limited athlete/coach buy‑in (18%). Heat acclimation and acclimatisation interventions typically began 3–5 weeks before competition in hot environments (45% and 44% respectively) and lasted 2–4 weeks (60% and 54% respectively). Active heat acclimation was typically prescribed for a minimum of 2 (2–3) weekly exposures to a maximum of 5 (4–6), with sessions lasting from 45 (30–60) to 90 (75–120) min. Active heat acclimatisation sessions were longer, at 60 (40–60) to 120 (90–180) min. For acclimation and acclimatisation, most practitioners reported that weekly training intensity (46% and 49%) and session frequency (70% and 76%) were consistent with normal training, while weekly volume was either maintained (42% and 50%) or decreased slightly (42% and 38%). CONCLUSION: Around half of practitioners implemented HT within one month of competition and for ≥2 weeks, consistent with current evidence-based guidelines. Active acclimatisation sessions were typically longer than active acclimation sessions. Further insight is needed from practitioners working with non-endurance athletes due to low representation (27%). HT guidelines for high-performance environments should also consider rigid training structures and athlete/coach engagement, given their influence on implementation.
Read CV Josh ElliottECSS Paris 2023: OP-PN22
INTRODUCTION: Although heat-related strain during intermittent exercise is well documented, direct comparisons between contrasting environments (i.e., hot-dry (HD) and warm-humid (WH) environments), especially between sexes, remain limited. This study compared thermal, cardiovascular, and perceptual responses of male and female athletes during intermittent running under temperate (TEM), HD, and WH conditions. METHODS: Twenty-six intermittent-sport athletes (13 males, 13 females) completed three trials, each comprising two 30-min halves (first (H1) and second (H2) half) of high-intensity intermittent treadmill running in TEM (19.9 ± 0.4°C, 55.6 ± 1.5% RH, WBGT: 16.0 ± 0.5°C), HD (40.1 ± 0.4°C, 24.4 ± 1.5% RH, WBGT: 29.0 ± 0.5°C), and WH (31.3 ± 0.4°C, 80.3 ± 1.5% RH, WBGT: 29.3 ± 0.5°C). Exercise intensity was matched between sexes by prescribing running velocities across six zones as a percentage of individual peak sprint velocity. Gastrointestinal temperature (Tgi), skin temperature (Tsk), heart rate (HR), rating of perceived exertion (RPE), whole-body sweat rate (WBSR), and total distance were measured. Water was provided ad libitum, and participants rested in the laboratory before H2. RESULTS: Mean HR, WBSR, RPE, Tsk, and Tgi in H2 were higher in HD and WH compared with TEM (P≤0.004). Physiological and perceptual responses were largely similar between HD and WH (P≥0.280); however, HD elicited higher Tsk (P<0.001) and WBSR (P≤0.004), with an increase in mean HR from H1 to H2 (P=0.048). Although males covered a greater total distance than females (1775 m [1282, 2269]; P<0.001), physiological and perceptual responses did not differ by sex (P≥0.541). A sex × condition interaction was observed for WBSR (P=0.001), with greater values in males than females under HD and WH conditions (P<0.001). A sex × time interaction was observed for mean Tgi (P = 0.048), indicating a differential temporal response between sexes; however, no significant effects were detected at individual time points (P≥0.974). Increases in sweat rate (P<0.001) and HR (P≤0.009) were observed in H2 (compared to H1) for both HD and WH. Despite significant interaction for Tgi (P≤0.048) and RPE (P<0.001), no differences between halves were detected within conditions or sexes (P≥0.078). Similarly, females displayed similar mean Tsk across halves in all conditions (P≥0.835). In contrast, mean Tsk for males did not differ between halves in TEM (P=0.995) but was lower in H2 than H1 in both HD and WH (P≤0.009). CONCLUSION: When matched for WBGT, high-intensity intermittent treadmill running elicited comparable thermal, cardiovascular and perceptual strain across HD and WH in both sexes. However, HD still imposed greater thermal and cardiovascular strain than WH, as reflected by the higher Tsk, HR, and WBSR, despite comparable Tgi responses. The absence of cumulative heat strain across halves was likely attributable to heat dissipation during recovery in the cooler laboratory environment between the halves.
Read CV Joel PangECSS Paris 2023: OP-PN22