Hot environmental conditions can reduce work productivity/exercise performance and increase the incidence of exertional heat illness. In preparation for hot environments, individuals commonly complete heat acclimation protocols that initiate physiological and perceptual adaptations to reduce thermal strain and improve physical capabilities. However, conventional exercise-heat acclimation interventions can be costly and impractical, as they require access to an artificial hot environment and often require control of core temperature
during exercise. As such, there is a demand for a flexible heat acclimation intervention that can be easily incorporated into the daily training of athletes and military/occupational personnel. Therefore, the aim of this thesis was to develop a novel and practical post-exercise hot water immersion heat acclimation protocol.
Firstly, 6-days of submaximal exercise in temperate conditions followed by a hot water immersion induced hallmark heat acclimation adaptations during submaximal exercise in temperate and hot conditions and improved endurance exercise performance in the heat (Chapter 4). The initiated adaptations were also not specific to the clock-time of when heat exposures occurred (Chapter 5). Post-exercise hot water immersion also initiated hallmark heat acclimation adaptations in both endurance trained and recreationally active individuals
(Chapter 6). In addition, the decay of the induced adaptations following post-exercise hot water immersion is slow, with no observable loss of heat acclimation two weeks following the cessation of the protocol (Chapter 7).
The studies presented in this thesis demonstrate that the novel post-exercise hot water immersion intervention provides heat acclimation and reduces thermal strain during exercise in the heat. Future research is required to optimise this technique to improve its incorporation into different military/occupational or athlete scenarios and assess the impact of the intervention on the incidence of exertional heat illness.