Cardiac and Thermal Strain of Elderly Adults Exposed to Extreme Heat and Humidity With and Without Electric Fan Use

Cardiac and Thermal Strain of Elderly Adults Exposed to Extreme Heat and Humidity With and Without Electric Fan UseHeat-related morbidity and mortality are important health challenges posed by global climate change. 1 Electric fans provide a low-cost and accessible cooling intervention, although their effectiveness remains debatable.Due to theoretical risks of accelerated heat gain and dehydration, fan use is discouraged above ambient temperatures of approximately 35°C. 2 However, empirical data to support or refute their use during heat wave conditions are sparse.3 Fan use delays elevations in heart rate and core temperature of young adults exposed to 42°C. 4 However, it remains unknown if fans are effective in vulnerable populations, such as the elderly who display altered cardiovascular and thermoregulatory responses during heat exposure.5 We hypothesized that fan use would delay elevations in heart rate and core temperature of elderly adults exposed to extreme heat and humidity. Core Temperature No Fan FanA, The critical humidity at which rapid elevations in heart rate and core temperature occurred was evaluated in elderly adults exposed to stepwise increases in relative humidity while resting at 42°C.The protocol was performed without and with fan use.B, Error bars indicate 95% confidence intervals.The horizontal line indicates the mean.The inflection points for heart rate (P = .68)and core temperature (P = .11)did not differ between conditions.jama.com