Maximum Skin Wettedness after Aerobic Training with and without Heat Acclimation

ABSTRACTPurposeTo quantify how maximum skin wettedness (ωmax); that is, the determinant of the boundary between compensable and uncompensable heat stress, is altered by aerobic training in previously unfit individuals and further augmented by heat acclimation.MethodsEight untrained individuals completed an 8-wk aerobic training program immediately followed by 8 d of hot/humid (38°C, 65%RH) heat acclimation. Participants completed a humidity ramp protocol pretraining (PRE-TRN), posttraining (POST-TRN), and after heat acclimation (POST-HA), involving treadmill marching at a heat production of 450 W for 105 min in 37.5°C, 2.0 kPa (35%RH). After attaining a steady-state esophageal temperature (Tes), humidity increased 0.04 kPa·min−1. An upward inflection in Tes indicated the upper limit of physiological compensability (Pcrit), which was then used to quantify ωmax. Local sweat rate, activated sweat gland density, and sweat gland output on the back and arm were simultaneously measured throughout.ResultsPeak aerobic capacity increased POST-TRN by approximately 14% (PRE-TRN: 45.8 ± 11.8 mL·kg−1·min−1; POST-TRN: 52.0 ± 11.1 mL·kg−1·min−1, P
Source: Medicine and Science in Sports and Exercise - Category: Sports Medicine Tags: Applied Sciences Source Type: research