Inducing a heat-acclimated phenotype via repeated heat stress improves exercise
capacity and reduces athletes̓ risk of hyperthermia and heat illness. Given the
increased number of international sporting events hosted in countries with
warmer climates, heat acclimation strategies are increasingly popular among
endurance athletes to optimize performance in hot environments. At the tissue
level, completing endurance exercise under heat stress may augment endurance
training adaptation, including mitochondrial and cardiovascular remodeling due
to increased perturbations to cellular homeostasis as a consequence of metabolic
and cardiovascular load, and this may improve endurance training adaptation and
subsequent performance. This review provides an up-to-date overview of the
metabolic impact of heat stress during endurance exercise, including proposed
underlying mechanisms of altered substrate utilization. Against this metabolic
backdrop, the current literature highlighting the role of heat stress in
augmenting training adaptation and subsequent endurance performance will be
presented with practical implications and opportunities for future research.