Heat acclimatization blunts copeptin responses to hypertonicity from dehydrating exercise in humans.

ABSTRACT: Acclimatization favors greater extracellular tonicity from lower sweat sodium, yet hyperosmolality may impair thermoregulation during heat stress. Enhanced secretion or action of vasopressin could mitigate this through increased free water retention. Aims were to determine responses of the vasopressin surrogate copeptin to dehydrating exercise and investigate its relationships with tonicity during short and long-term acclimatization. Twenty-three participants completed a structured exercise programme following arrival from a temperate to a hot climate. A Heat Tolerance Test (HTT) was conducted on Day-2, 6, 9 and 23, consisting of 60-min block-stepping at 50% VO₂ peak, with no fluid intake. Resting sweat [Na⁺ ] was measured by iontophoresis. Changes in body mass (sweat

SUBMITTER: Stacey MJ 

PROVIDER: S-EPMC6139708 | biostudies-literature | 2018 Sep

REPOSITORIES: biostudies-literature