By Eric Hamilton, University of Florida News
Every year, more than 100,000 people are treated for heat injury in the U.S., a number that’s been rising as the world rapidly warms. Heatstroke, the most damaging form, can make people lose consciousness, suffer organ injury, and even, rarely, die.
While most victims of heatstroke seem to recover in short order, a new study from University of Florida researchers reveals that a single exposure to heatstroke can lead to lasting, multi-organ damage and obesity in mice for months afterward — equivalent to many years in a human lifespan.
“The animals appeared to recover over a few days, but their hearts metabolically crashed two weeks later, which is when physicians often stop following human patients,” said Thomas Clanton, Ph.D., a professor of applied physiology and kinesiology at UF who led the new study.
What’s more, mice fed a high-fat Western diet after recovering from heatstroke, which further stresses the body, packed on even more weight. Both male and female mice showed this chronic deterioration after heatstroke, but male mice suffered the worst effects.
The findings show how important it is to prevent and limit heat injury before it occurs, the authors say, by hydrating and cooling down when symptoms like fatigue set in. There is no established treatment for chronic heatstroke injury. But future research could help identify ways to limit the long term damage in people.
With funding from the U.S. Army Medical Research and Development Command, Clanton’s lab developed their mouse model of heatstroke to help the military protect recruits and soldiers from the effects of heat injury. The Army’s improved procedures in recent years have greatly reduced the number of soldiers facing severe heatstroke.
But Clanton’s team noticed that some animals — and humans, too — seemed to experience lasting effects even after recovering from the initial injury, much like the chronic effects of concussions or viral infections that can last for years or even decades.
By following mice for three months after a single exposure to heatstroke, the researchers discovered that the heat injury weakened the animals’ hearts, made the animals eat more food and put on weight, and disrupted their metabolism of carbohydrates.
While the effects in mice may not translate directly to humans, Clanton and his colleagues are planning to follow people who have suffered heatstroke to further understand the factors that cause the long term problems.
Their goal is to someday identify treatments that could help people recover more quickly, which could become even more important as the climate continues to heat up.
“We think there’ll be more of this chronic heat injury as we face a warming environment,” Clanton said.
This piece was originally published at https://news.ufl.edu/2025/01/heatstroke/. Banner photo: A worker shields himself from the sun (iStock image).
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