Broiling in a Heat Wave? Wet T-shirt Can Safely Cool You Down

MONDAY, April 13, 2020 (HealthDay News) -- A wet T-shirt may cool seniors more effectively than an electric fan in hot, humid weather, reducing their risk of heat-related illness, according to a new study.

It included adult volunteers, average age 68, who sat for two hours in a room with an air temperature of 108 degrees Fahrenheit and a relative humidity of 34%.

Volunteers did three tests. In one, they wore a dry cotton T-shirt. In another, they wore a cotton T-shirt soaked with about 2 cups of water. In the third, they donned a similarly soaked T-shirt and sat in front of an electric fan.

Volunteers could have as much lukewarm drinking water as they wanted during the sessions, in which their heart rate, blood pressure, core body temperature and changes in body mass were checked every 30 minutes.

Their wet shirts were weighed before and after the sessions to determine how much sweat and water had evaporated. As expected, the wet T-shirt/fan session resulted in the most evaporation, and the dry T-shirt, the least.

The wet shirt alone was the most effective at easing heat strain -- assessed by changes in core body temperature -- but heat strain levels were the same with the dry T-shirt and the wet T-shirt and fan, the study found.

The study was recently published in the Journal of Applied Physiology.

"These findings suggest that wearing a water-soaked T-shirt in heat wave conditions can [lessen] heat strain, while electric fan use in combination with a water-soaked T-shirt has no effect on heat strain compared to wearing a dry T-shirt alone," said researchers led by Craig Crandall, a professor at the Institute of Exercise and Environmental Medicine at Texas Health Presbyterian Hospital of Dallas.

"This information should be incorporated into public health messaging regarding effective cooling strategies to reduce the risk of heat-related health problems during extreme heat events," the authors said in a journal news release.

More information

The U.S. National Institute on Aging offers hot weather safety tips for older adults.

SOURCE: Journal of Applied Physiology, news release, April 2, 2020

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