Electric Fans Ineffective for lowering core body temperatures of elderly in Extreme Heat: JAMA
Researchers have established that electric fans did not reduce core body temperatures of elderly individuals under extreme heat indoors, especially as temperature increased to 33°C and beyond. A recent study was published in the journal JAMA Network by Fergus K. and colleagues.
Electric fans have been suggested as an inexpensive means to reduce heat stress among very elderly individuals aged 65 and older, especially based on earlier biophysical modeling and works in younger adults. This study was designed to determine the effect of exposure to an electric fan on core temperature and heart rate in older adults who were exposed to indoor temperatures similar to those during recent North American deadly heat waves.
The subjects (≥65 years) were exposed to high indoor temperatures of more than 33°C, simulating conditions that are usually experienced during a heat wave. The core temperature and heart rate of the participants were recorded throughout the exposure period while measuring the impact of electric fans use. This would measure if fans can limit the rise in core body temperature and provide cardiovascular relief under such extreme conditions.
The experiment reported a lack of effective cooling by electric fans on peak core temperatures in older individuals exposed to high indoor heat:
• Peak core temperature was unaltered by fan use, meaning that it showed inefficient reduction of dangerous heat accumulation in the elderly.
• Besides end-exposure core temperature and heart rate declines, these decreases were small and below thresholds for clinical significance.
• However, the core temperature and heart rate reduction both were small, without question not more than a marginal effect among subjects, and therefore of no biomedical significance.
• These findings are in keeping with previous biophysical models which suggested that cooling by fans had little role to play in reducing body temperature in older individuals at ambient temperatures above 33-35°C.
Thus, electric fans alone cannot be used as a cooling intervention, especially when temperatures rise above 33°C in extreme indoor heat environments. These findings further indicate the alternative cooling solution urgently needed for older adults in a world with rising global temperatures and deadly heat waves.
Reference:
O’Connor, F. K., Meade, R. D., Wagar, K. E., Harris-Mostert, R. C., Tetzlaff, E. J., McCormick, J. J., & Kenny, G. P. (2024). Effect of electric fans on body core temperature in older adults exposed to extreme indoor heat. JAMA: The Journal of the American Medical Association. https://doi.org/10.1001/jama.2024.19457
