PhotoConsumers everywhere aren’t shy about cranking up the A/C or turning on fans when the weather gets hot, but could it be negatively affecting older members in your household?

New research from the UT Southwestern Medical Center shows that using fans to cool things down in extreme heat conditions increases health risks for seniors. The reason, experts say, is that many older consumers no longer have the capacity to sweat optimally and make good use of a fan’s cooling breezes. In fact, findings showed that seniors’ internal temperatures and heart rates climbed under extreme heat conditions when they tried to use a fan.

“We know that fans keep young adults cooler by increasing 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,” said Dr. Craig Crandall, member of the Institute for Exercise and Environmental Medicine and professor at UT Southwestern.

Higher heart rate and internal temperature

The researchers came to these conclusions after analyzing the physiological responses that seniors had while in a high-heat and high-humidity environment. Participants between the ages of 60 and 80 were placed in a room that clocked in at 107 degrees. Humidity was increased from 30% to 70% over a two-hour period.

As the researchers expected, the participants’ heart rate and internal body temperature rose throughout the session as the humidity increased. The study was conducted in two trials – one where participants used an electric fan and one where they did not.

Surprisingly, participants who made use of a fan had heart rates that were, on average, 10 beats higher per minute than those without a fan. Their internal temperatures were also 0.5 degrees Fahrenheit higher.

Extreme heat

The researchers stress that their findings apply primarily for extreme heat and humidity conditions. However, they say that it should be something that consumers keep in mind if they’re experiencing a heat wave.

“Although differences were small, the cumulative effect could become clinically important during prolonged heat exposure, such as during extreme heat waves,” said Crandall.

The full study has been published in JAMA.

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