Jun 3, 2016 - Ella F. Walker, Jo Corbett, James R. House, Michael J. Tipton. University of Portsmouth, Portsmouth, United Kingdom. (No relationships ...
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Thematic Poster - Thermoregulation and Heat Stress Friday, June 3, 2016, 1:00 PM - 3:00 PM Room: 110
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Chair: Lawrence E. Armstrong, FACSM. University of Connecticut, Storrs, CT. (No relationships reported)
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Board #1 June 3, 1:00 PM - 3:00 PM Influence Of Aerobic Fitness On The Thermophysiological Responses In Compensable And Uncompensable Heat Stress Ella F. Walker, Jo Corbett, James R. House, Michael J. Tipton. University of Portsmouth, Portsmouth, United Kingdom. (No relationships reported)
PURPOSE: To examine the influence of aerobic fitness in groups matched for anthropometric characteristics on the thermal and thermoeffector responses in compensable (CO) and uncompensable (UN) heat stress, during exercise at matched relative and absolute work rates. Previous work has been confounded by differences in body characteristics and the selection of external work rate. METHODS: Eight high (HI) (mean [SD] V̇O2max = 58.73[6.28] mL.kg-1.min-1) and eight low aerobic fitness (LO) (46.53[6.73] mL.kg-1.min-1) males, matched for body mass, surface area and % body fat volunteered. LO cycled at 60 W (ABS) in 34 °C, 20 % rh. HI completed the same condition, plus an additional test to match the relative intensity of the LO at ABS as a % of V̇O2max (REL). There were two phases in each trial: 1) Compensable phase - 60 minutes at the specified external work rate, CO was confirmed by a plateau in rectal temperature (Tre). 2) Uncompensable phase – immediately following the compensable phase, ambient temperature (T db) was increased by 1 °C every 5 minutes, UN was confirmed by an inflection in Tre (Treinfl). Tdb, Tre, change in Tre from rest (∆Tre), metabolic heat production (M) back sweat rate (SRBack) and laser Doppler forearm skin blood flow (SkBF) were measured at end of the compensable phase and T reinfl identified. Data were analysed by independent t-tests. RESULTS: 1) Compensable phase - there were no differences in Tdb, Tre, ∆Tre or SkBF between fitness groups in ABS or REL (all p=>0.05) or M in ABS (p=0.633). HI had higher SRBack in both ABS (p=0.002) and REL (p0.05) or M in ABS (p=0.361) at T reinfl. HI had higher SRBack in both ABS (p=0.005) and REL (p
