Heat acclimation improves heat exercise tolerance and heat dissipation in individuals with extensive skin grafts.
Burn survivors with extensive skin grafts have impaired heat dissipation and thus heat tolerance. This study tested the hypothesis that heat acclimation (HA) improves these factors in this population. Thirty-four burn survivors were stratified into highly [>40% body surface area (BSA) grafted, n = 15] and moderately (17-40% BSA grafted, n = 19) grafted groups. Nine healthy nonburned subjects served as controls. Subjects underwent 7 days of HA involving 90 min of exercise at ∼ 50% peak oxygen uptake in 40°C, 30% relative humidity. On days 1 and 7, subjects exercised in the heat at a fixed rate of metabolic heat production. Pre-HA, all controls and 18/19 subjects in the 17-40% group completed 90 min of exercise. Conversely, heat exercise tolerance was lower (P < 0.01) in the > 40% group, with 7/15 subjects not completing 90 min of exercise. Post-HA, heat exercise tolerance was similar between groups (P = 0.39) as all subjects, except one, completed 90 min of exercise. Pre-HA, the magnitude of the increase in internal temperature during exercise occurred sequentially (P ≤ 0.03) according to BSA grafted (>40%: 1.6 ± 0.5°C; 17-40%: 1.2 ± 0.3°C; control: 0.9 ± 0.2°C). HA attenuated (P < 0.01) increases in internal temperature in the control (by 0.2 ± 0.3°C), 17-40% (by 0.3 ± 0.3°C), and > 40% (by 0.3 ± 0.4°C) groups, the magnitude of which was similar between groups (P = 0.42). These data indicate that HA improves heat tolerance and dissipation in burn survivors with grafted skin, and the magnitude of these improvements are not influenced by the extent of skin grafting.
Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital of Dallas and Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas; Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, New York;
Zachary J
ZJ
Schlader
Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital of Dallas and Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas; Department of Health, Human Performance, and Recreation, University of Arkansas, Fayetteville, Arkansas;
Matthew S
MS
Ganio
Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital of Dallas and Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas; Department of Biology, University of Colorado at Colorado Springs, Colorado;
James
J
Pearson
Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital of Dallas and Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas; School of Sport, Exercise and Rehabilitation Sciences, University of Birmingham, Birmingham, UK;
Rebekah A I
RA
Lucas
Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital of Dallas and Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas;
Daniel
D
Gagnon
Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital of Dallas and Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas; Department of Kinesiology, Texas Woman's University, Denton, Texas; and.
Eric
E
Rivas
Department of Physical Medicine and Rehabilitation, University of Texas Southwestern Medical Center, Dallas, Texas.
Karen J
KJ
Kowalske
Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital of Dallas and Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas; craigcrandall@texashealth.org.
Craig G
CG
Crandall
D000064:Acclimatization / Q000502:physiology*; D000328:Adult; D001831:Body Temperature / Q000502:physiology; D001833:Body Temperature Regulation / Q000502:physiology*; D002056:Burns / Q000601:surgery; D017079:Exercise Tolerance / Q000502:physiology*; D005260:Female; D005334:Fever / Q000503:physiopathology; D006439:Hemodynamics / Q000502:physiology; D006358:Hot Temperature; D006801:Humans; D008297:Male; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology; D016038:Skin Transplantation; D013546:Sweating / Q000502:physiology
burn injury; heat adaptation; heat loss; heat tolerance; hyperthermia; skin grafting