Abstract
Purpose: The aims of this study are to explore the effectiveness of mixed active and passive heat acclimation (HA), controlling the relative intensity of exercise by heart rate (HR) in paratriathletes (PARA), and to determine the adaptation differences to able-bodied (AB) triathletes.Methods: Seven elite paratriathletes and 13 AB triathletes undertook an 8-day HA intervention consisting of five HR-controlled sessions and three passive heat exposures (35°C, 63% relative humidity). On the first and last days of HA, heat stress tests were conducted, whereby thermoregulatory changes were recorded during at a fixed, submaximal workload. The AB group undertook 20 km cycling time trials pre- and post-HA with performance compared to an AB, non-acclimated control group.Results: During the heat stress test, HA lowered core temperature (PARA: 0.27 ± 0.32°C; AB: 0.28 ± 0.34°C), blood lactate concentration (PARA: 0.23 ± 0.15 mmol l−1; AB: 0.38 ± 0.31 mmol l−1) with concomitant plasma volume expansion (PARA: 12.7 ± 10.6%; AB: 6.2 ± 7.7%; p ≤ 0.047). In the AB group, a lower skin temperature (0.19 ± 0.44°C) and HR (5 ± 6 bpm) with a greater sweat rate (0.17 ± 0.25 L h−1) were evident post-HA (p ≤ 0.045), but this was not present for the PARA group (p ≥ 0.177). The AB group improved their performance by an extent greater than the smallest worthwhile change based on the normal variation present with no HA (4.5 vs. 3.7%).Conclusions: Paratriathletes are capable of displaying partial HA, albeit not to same extent as AB triathletes. The HA protocol was effective at stimulating thermoregulatory adaptations with performance changes noted in AB triathletes.
Highlights
Competitive sporting events are commonly held in hot and/or humid environments; strategies are commonly sought to attenuate the deterioration typical of endurance performance in such conditions (Daanen et al, 2018); one such strategy that is commonly used by athletes is heat acclimation (HA)
The PARA group were older than AB control group (AB-CON) (p = 0.009), but there were no significant differences in body mass, peak rate of oxygen uptake, maximum aerobic power output (PO), or aerobic lactate threshold (AeLT) between groups (p ≥ 0.352; Table 1)
thermal sensation (TS) was significantly lower during TT2 for the AB-ACC group (p = 0.013); there was no significant change in the AB-CON group (p = 0.090), nor was there an effect of trial on rating of perceived exertion (RPE) in either group (p ≥ 0.388)
Summary
Competitive sporting events are commonly held in hot and/or humid environments; strategies are commonly sought to attenuate the deterioration typical of endurance performance in such conditions (Daanen et al, 2018); one such strategy that is commonly used by athletes is heat acclimation (HA). To provide a constant heat stress across HA, isothermic protocols have been employed, whereby the external workload is manipulated within- and between-HA sessions to maintain a Tc of ~38.5°C (Gibson et al, 2015; Neal et al, 2016; Ruddock et al, 2016). These approaches bring the financial burden of measuring Tc via ingestible sensors or participant discomfort from rectal temperature assessment. Initial evidence suggests that this approach may be efficacious in invoking HA in soccer players (Philp et al, 2017)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
