Core temperature responses in well-healed burn survivors during exercise heat stress: effect of cooling modalities

Abstract

Introduction: Every year, ~150,000 patients are treated in the United States with burn-related injuries. Previously, our group has shown that ~75% of burn survivors have a maximal aerobic capacity in the lowest 20th percentile rankings, relative to sex and age-adjusted non-burned individuals. This level of impairment is strongly associated with cardiovascular-specific, as well as all cause, morbidity, and mortality. Moreover, burn injuries that require grafting impair thermoregulation, and the subsequent increases in skin and core temperature may dissuade these individuals from engaging in exercise and/or physical activity. Low-energy cooling strategies have potential to attenuate increases in core temperature in burn survivors, which may promote regular physical activity. Thus, the purpose of this study was to evaluate the efficacy of low-energy cooling modalities on thermoregulatory responses during physical activity in the heat. Methods: Twenty-four adults with NO-BURN (n = 9), MODERATE burns (20-40% body surface area burned, n = 7), or LARGE burns (> 40% body surface area burned, n = 8) walked for one hour at a moderate intensity (rate of metabolic heat production of 4.5 W/kg body mass) in an environmental chamber (39°C, 40% RH). Burn survivors were at least 2 years post-injury. Participants performed this activity four times, with the following modalities randomly applied throughout each trial on separate days: no cooling (i.e., control), fan at 4 m/s (FAN), water spray (WS, minimum 10-50 g every 5 min, scaled to burn area size), or WS+FAN. Core temperature (Tcore) was recorded throughout each trial via a telemetric pill. Final Tcore values for each cooling modality were compared against the no cooling condition. Results: For the LARGE burn group, WS reduced end-exercise Tcore by 0.37°C (range 0.09 to 0.66°C) compared with no cooling ( p = 0.01). FAN and WS+FAN did not impact end-exercise Tcore for the LARGE burn group ( p ≥ 0.48). No cooling modality affected Tcore for the MODERATE burn group ( p ≥ 0.12) or the NO-BURN group (p ≥ 0.55). Conclusion: At the assessed workload and environmental condition, the efficacy of the applied cooling modalities on Tcore responses for burn survivors appears to be dependent on both the selected modality and the size of the burn surface area. Namely, WS attenuated the increases in Tcore in participants with LARGE burn injuries, but FAN and WS+FAN did not attenuate Tcore responses in any group. Supported by NIHGrant R01GM068865 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.