Influence and Mechanisms of Action of Environmental Stimuli on Work Near and Above the Severe Domain Boundary (Critical Power)

Abstract

The critical power (CP) concept represents the uppermost rate of steady state aerobic metabolism during work. Work above CP is limited by a fixed capacity (W′) with exercise intensity being an accelerant of its depletion rate. Exercise at CP is a considerable insult to homeostasis and any work done above it will rapidly become intolerable. Humans live and exercise in situations of hypoxia, heat, cold and air pollution all of which impose a new environmental stress in addition to that of exercise. Hypoxia disrupts the oxygen cascade and consequently aerobic energy production, whereas heat impacts the circulatory system’s ability to solely support exercise performance. Cold lowers efficiency and increases the metabolic cost of exercise, whereas air pollution negatively impacts the respiratory system. This review will examine the effects imposed by environmental conditions on CP and W′ and describe the key physiological mechanisms which are affected by the environment. Graphical Abstract

Effect of acute heat exposure on the determination of critical power and W′ in women and men

“…This will provide more insight into the response to exercise with acute heat exposure and ensure useful support to enhance the preparation of athletes, employing the CP concept, for training and competition in hot environments. In accordance with the review of Richard and Koehle (2022), we hypothesized that CP would be lower, whereas W ′ would not be influenced in hot environmental conditions, with no difference between women and men.…”

“…Despite the broad application of the CP concept, the impact of heat exposure on the concurrently measured parameters of the power-duration relationship per se, i.e. CP and W ′ , is scarcely documented (Richard & Koehle, 2022). Investigating this matter might be of interest both from a performance and health perspective, as more athletes (recreational as well as elite) have to perform in hot environmental conditions.…”