Electric fan use during heat waves: Turn off for the elderly?

In their Discovery article, Ravanelli & Jay1 make a compelling argument that should change our perception of electric fan use during heat waves. Public health agencies generally discourage fan use above air temperatures of ～35°C (95°F), due to the concern that increased air velocity will only serve to accelerate dry heat gain and dehydration. However, as Ravanelli & Jay1 discuss, greater heat gain during fan use is far outweighed by increased sweat evaporation, the latter of which can be offset by drinking less than one cup of water per hour. Consequently, fan use delayed the increase in heart rate and internal body temperature of young adults exposed to a humidity ramp protocol performed at 36°C (97°F) and 42°C (108°F)2. These findings are particularly important given a general lack of knowledge regarding the effectiveness of fan use during heat waves