Biophysical modelling predicts unreliable core temperature responses on healthy older adults using electric fans at residential homes during heatwaves

Electric fans are proposed to mitigate indoor heat stress during heatwaves. Fan cooling threshold temperatures were determined by biophysical models. However, such models could only account for sweating adjustment and disregarded evident cardiovascular impairment in older adults. This study demonstrated the contribution of cardiovascular function adjustment to core temperature responses. Results revealed that focusing just on sweating adjustment greatly underestimated the actual heat stress experienced by older adults. It is not recommended to use biophysical models to determine the threshold temperature of electric fan use for older adults during heatwaves because cardiovascular adjustment was not possible.

Automated summary

Electric fans are suggested for alleviating indoor heat stress, but existing biophysical models fail to consider cardiovascular impairment in older adults. This study highlights the importance of cardiovascular function in core temperature responses, showing that relying solely on sweating adjustment underestimates heat stress in older adults. Thus, using biophysical models to determine fan use threshold temperature for older adults during heatwaves is not recommended due to the lack of cardiovascular adjustment.