References
mass loss, Thirst
DEHYDRATION, HEAT
Schematic of experimental design and measures for passive and active dehydration (DEHydration) and euhydration (EUHydration) trials.Change in plasma volume (∆PV) during (i) passive DEHydration (Grey area: 40 °C, 60% RH; White area: 25 °C, 35% RH) and active DEHydration (4 min at ~90% HRChange in plasma osmolality (∆PPartitioned mass exchanges during passive heat stress (P_; 40 °C, 60% RH) and active heat stress (A_; 4-min bouts at ~90% HRPre- and post-thirst ratings following ingestion of a standardised small volume of water (0.1% ΔBM) at each of 1, 2, and 3% reductions in body mass during passive DEHydration (Thirst as a function of plasma osmolality (Posm) during DEHydration from 0 to 3% body mass via passive heat stress (P_DEH; 40 °C, 60% RH) and active heat stress (A_DEH; 4-min bouts at ~90% HRTwo-hour fluid balance following passive heat-stress DEHydration (40 °C, 60% RH, P_DEH) and active heat-stress DEHydration (4-min exercise bouts at ~90% HRGeneral Characteristics of Participants.Data are mean ± standard deviation. Duration of heat stress required to achieve 3% gross loss of body mass during passive and active heat stress, with negligible fluid replacement (DEHydration), and with water intake matched to fully replace mass loss (EUHydration).∆BM; Change in body mass; Summary of findings for the four main research questions.P = passive; A = active; D = DEHydration; BM = body mass.