The influence of short-term heat acclimation with permissive dehydration on temperate exercise performance in highly trained athletes

Long-term (≥ 10 day) heat acclimation (HA) has been shown to be ergogenic under cool ambient conditions [1]. Potential mechanisms underpinning the ergogenic effects of long-term HA include increased maximal oxygen uptake, possibly mediated by plasma volume (PV) expansion and an increased maximal cardiac output [1], as well as reduced physiological strain through improved thermoregulation [2]. Recently, short-term (5 day) HA with restricted fluid intake (STHADe) has been shown to augment PV expansion and accelerate HA relative to euhydrated HA [3]; performance improvements in the heat have been documented in highly-trained men following this regime [4]. This study examined the ergogenic effect of STHADe on exercise in a temperate environment.