Electric Fans May Be Risky in Extreme Heat

More Study Needed to Prove Safety, Review Suggests

By Salynn Boyles
WebMD Health News

Reviewed by Brunilda Nazario, MD

July 12, 2012 -- Already this summer much of the nation has faced record setting, triple-digit heat, and it's only mid-July.

Now, as heat waves become more common, a new report questions the safety of a long-relied-upon method for staying cool on sweltering days: the electric fan.

While the review found little evidence of health harms linked to the use of electric fans among people without air conditioning, researchers concluded that better studies are needed to fully understand their impact during heat waves.

"The main implication of this review is that quality research is needed to resolve the ongoing uncertainty about the benefits and harms of using electric fans during heat waves," Katie Carmichael of the U.K.'s Health Protection Agency (HPA) said in a news briefing.

Fans May Raise Body Temp

Conducted by the international nonprofit research group The Cochrane Collaboration, the review was done for the benefit of the public and health policymakers, says Virginia Murray, who heads the HPA's division of Extreme Events and Health Protection.

She explains that following a 2003 heat wave that killed 30,000 Europeans, health officials in England developed a heat wave plan for the country that is reviewed and updated annually.

"We wondered if it would be useful to encourage the use of electric fans," she tells WebMD.

A concern is that they may do more harm than good when temperatures are very high by heating the body instead of cooling it, Murray says. At high temperatures fans may also encourage excess sweating, which can lead to dehydration and electrolyte imbalance, which can affect the proper functioning of everything from your heart to your nerves.

This may be especially true for the most vulnerable populations, including the very old and very young, and people with serious health conditions.

The research review turned up no studies that directly compared health outcomes among people who did and did not use electric fans during heat waves.

Findings from less rigorous studies were mixed, with some suggesting that fans reduced heat-related injury while others found that they made things worse.

Based on this evidence, the researchers concluded that electric fans could potentially do more harm than good at temperatures above 95 degrees.

But "our review does not support or refute the use of electric fans during a heat wave," Carmichael noted.

Having a Heat Wave: Here's What to Do

So what can you do to avoid heat-related injury when the temperature soars?

The American Red Cross recommends:

  • Drink plenty of fluids, even if you don't feel thirsty. And avoid drinks with caffeine or alcohol.
  • Slow down, stay inside, and avoid strenuous exercise during the hottest part of the day.
  • Check on family, friends, and neighbors who do not have air conditioning, as well as those who spend much of their time alone or who are more likely to be affected by the heat.
  • Wear lose fitting, lightweight, light-colored clothing. Dark colors absorb the sun's rays.
  • Take frequent breaks if you work outdoors.
  • And if you don't have air conditioning, find a place that does (malls, libraries, theaters).

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SOURCES: Gumpta, S. The Cochrane Library, July 11, 2012. Katie Carmichael, Health Protection Agency, London. Virginia Murray, head of Extreme Events and Health Protection, Health Protection Agency, London, U.K. News release, Wiley Science Newsroom. Red Cross: "Heat Wave Safety Checklist." NOAA, summer weather forecast 2012, March 20, 2012.

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