Cardiovascular Responses in Burn Survivors During Exercise

This project will identify the efficacy of cooling modalities aimed to attenuate excessive elevations in skin and internal body temperatures, and associated indices of cardiovascular stress, during physical activity in well-healed burn survivors. The investigators will conduct a randomized crossover design study. Non-burned control subjects and subjects who experienced burns covering 20% or more of their body surface area will be investigated. Subjects will exercise in heated environmental conditions while receiving no cooling (control) as well as skin wetting.

Within the United States, 500,000+ individuals are enduring the long-term consequences of severe burn injuries covering 20% or more of their body surface area, with upwards to 11,000 individuals experiencing such an injury per year. These burn injuries can severely compromise body temperature regulation, owing to permanent impairments in the primary thermoeffectors necessary to dissipate heat, namely profoundly blunted skin blood flow and sweating responses in the injured skin. The investigators propose that this heat intolerance deters burn survivors from participating in physical activity, including activities of daily living, necessary to avoid the adverse cardiovascular and metabolic sequela of a sedentary lifestyle. Consistent with hypothesis, years after the injury burn survivors have a very low aerobic capacity; greater all-cause mortality rates; greater hospitalization days for circulatory diseases; and suffer from greater incidences of ischemic heart disease, heart failure, diabetes, and cerebrovascular disease (including stroke) relative to matched non-burned cohorts. The primary goal of this project is to identify modalities to attenuate excessive elevations in skin and core body temperatures, and accompanying cardiovascular stress, during physical activity in well-healed burn survivors. The implementation of such modalities will eliminate heat intolerance as a barrier to participation in activities that are necessary to improve/maintain cardiovascular health in this vulnerable population. This project will investigate whether increased skin wetness will restore otherwise impaired evaporative cooling of well-healed burn survivors, with the extent of that improvement predicated on the environmental conditions and the percentage of body surface area burned.