Electric Fans May Worsen Effects of High Heat and Humidity on Older Adults

Heart specialists from University of Texas Southwestern Medical Center say that using electric fans to relieve high levels of heat and humidity may in fact have the opposite effect for older adults, based on a recent study (JAMA. 2016;316[9]:989-991).

Professor Craig Crandall, PhD, of the Institute for Exercise and Environmental Medicine at Texas Health Presbyterian Hospital (Dallas, TX), said in a statement: “We know that fans keep young adults cooler by increasing the evaporation of sweat….We surmise that age-related impairments in sweating capacity make fans an ineffective means of cooling for the elderly during exceptionally hot days, and may, in fact, increase thermal and cardiac strain.”

Researchers studied the physiological responses of a small group of elderly patients in a high-heat, high-humidity environment. Participants between the ages of 60 and 80 were observed for approximately two hours in a 107°F room and a humidity level that was gradually increased from 30% to 70%. Not surprisingly, both heart rate and internal body temperature rose as the humidity level in the room rose. 

The eight individuals in the study were tested under those conditions without a fan and, on a separate occasion, with an electric fan. Unexpectedly, the participants’ heart rates were 10 beats per minute higher and their internal temperatures 0.5°F higher when a fan was part of the experimental environment. 

Although these findings suggest that fan use may be counterproductive for seniors during heat waves, the investigators propose that fan use may still be beneficial under less extreme environmental conditions, though this needs to be confirmed.

Dr Crandall recommended that seniors living without air conditioning should stay hydrated during severe heat waves and seek an air-conditioned environment such as a friend or family member’s home, a community center, or a shopping mall. —Amanda Del Signore