High thermoregulatory strain during competitive paratriathlon racing in the heat

Purpose: Paratriathletes may display impairments in autonomic (sudomotor and/or vasomotor function) or behavioural (drinking and/or pacing of effort) thermoregulation. As such, this study aimed to describe the thermoregulatory profile of athletes competing in the heat. Methods: Core temperature (Tc) was recorded at 30 s intervals in 28 mixed-impairment paratriathletes during competition in a hot environment (33oC, 35-41% relative humidity, 25-27oC water temperature), via an ingestible temperature sensor (BodyCap e-Celsius). Furthermore, in a subset of 9 athletes, skin temperature (Tsk) was measured. Athletes’ wetsuit use was noted whilst heat illness symptoms were self-reported post-race. Results: Twenty-two athletes displayed a Tc ≥39.5oC with 8 athletes ≥40.0oC. There were increases across the average Tc for swim, bike and run sections (p≤0.016). There was no change in Tsk during the race (p≥0.086). Visually impaired athletes displayed a significantly greater Tc during the run section than athletes in a wheelchair (p≤0.021). Athletes wearing a wetsuit (57% athletes) had a greater Tc when swimming (p≤0.032) whilst those reporting heat illness symptoms (57% athletes) displayed a greater Tc at various timepoints (p≤0.046). Conclusions: Paratriathletes face significant thermal strain during competition in the heat, as evidenced by high Tc, relative to previous research in able-bodied athletes, and a high incidence of self-reported heat illness symptomatology. Differences in the Tc profile exist depending on athletes’ race category and wetsuit use.