Effects of Burn Injuries on Thermoregulatory and Cardiovascular Responses in Soldiers: Implications for the Standards of Medical Fitness

This project tested the hypothesis that burn survivors could exercise for 30 min without excessive elevations in core body temperature, regardless of the total body surface area TBSA burned or environmental temperature. Ten subjects cycled for 60 min at 1 a moderate intensity 978 watts in a thermoneutral environment 24 deg C, MODNEU, 2 a moderate intensity 10017 watts in a hot environment 39 deg C, MODHOT, and 3 a low intensity 6510 watts in a hot environment 39 deg C, LOWHOT. Burn injuries were simulated by covering 0, 20, 40, or 60 of the individuals TBSA with an absorbent material that prevented sweat evaporation. Changes in gastrointestinal temperature Tcore were analyzed at 15-min increments throughout exercise. For the MODNEU trial, there were no differences in Tcore between the TBSA coverage bouts at any time point during exercise. For the MODHOT trial, there were no differences in Tcore at 15 and 30 min of exercise regardless of the TBSA coverage, while Tcore was appreciably elevated P0.05 at 45 and 60 min of exercise for 20 TBSA bouts. For the MILDHOT trial, there were no differences in Tcore at any time point between TBSA bouts, with the sole exception of 60 simulated burn having a slightly greater Tcore 0.30.34 deg C P0.05 at 60 min of exercise relative to the 0 TBSA bout. These data indicate that individuals with up to 60 of their TBSA burned could exercise at a moderate intensity for 30 min, even in hot environmental conditions, without excessive elevations in body core temperature. Thus, burn survivors can benefit from exercise, without the risk of excessive hyperthermia, for up to 30 min in the heat or at least 60 min in an air-conditioned space.