Self-paced exercise performance in the heat with neck cooling, menthol application, and abdominal cooling

Abstract

ObjectivesTo investigate whether the exercise performance benefits with neck cooling in the heat are attributable to neck-specific cooling, general body cooling, a cooler site-specific thermal perception or a combination of the above. DesignCounter-balanced crossover design. MethodsTwelve healthy participants cycled in the heat (34°C, 30% relative humidity), at a power output (PO) self-selected to maintain a fixed rating of perceived exertion (RPE) of 16. Each participant underwent four experimental trials: no cooling (CON), neck cooling (NEC), abdominal cooling (ABD), or neck cooling with menthol (MEN). Participants cycled for 90min or until their workload reduced by <70% of their initial PO. Changes in PO, rectal temperature (Tre), mean skin temperature (Tsk), whole-body thermal sensation (TSwb) and thermal sensation of the neck (TSneck) were recorded throughout. ResultsThe mean reduction in PO throughout exercise was similar (p=0.431) for CON (175±10W), NEC (176 ±12W), ABD (172±13W) and MEN (174±12W). The ΔTre at the end of exercise was similar (p=0.874) for CON (0.83±0.5°C), NEC (0.85±0.5°C), ABD (0.82±0.5°C) and MEN (0.81±0.5°C). TSwb was cooler (p<0.013) in MEN (125±8mm) compared to CON (146±19mm), NEC (135±11mm) and ABD (141±16mm). ConclusionsNo differences in exercise performance or thermal strain were observed in any of the cooling trials compared to the CON trial, despite significantly cooler TSwb values in the MEN and NEC trials compared to the CON trial. These findings differ from previous observations and highlight that the benefit of neck cooling may be situation dependent.