Repeated-sprint performance in combined heat and hypoxia: Current evidence

While the efficacy of repeated-sprint training in hypoxia (RSH) for enhancing performance is widely recognized, repeated-sprint training in combined heat and hypoxia (RSH+H) has recently attracted attention as a potential extension of conventional RSH. The present review summarizes acute performance and physiological responses to repeated-sprint exercise in combined heat and hypoxia (H+H). Unlike endurance performance, repeated-sprint performance appears to be preserved during H+H exposure in the absence of hyperthermia. Notably, the H+H condition may also modify physiological responses associated with RSH, including muscle oxygenation and anaerobic energy production. However, findings remain inconsistent across studies, and it is currently unclear whether these acute responses translate into greater training adaptations or performance gains than those achieved with RSH alone. The available evidence is further limited by the small number of studies, the predominance of acute experimental designs, and the lack of diverse participants. Overall, RSH+H should be regarded as an emerging strategy that warrants further investigation, particularly with respect to long-term training adaptations and optimal combinations of heat and hypoxia.