Israeli children cooled off in a water fountain near Jerusalem’s Old City on Aug. 13, as temperatures in Jerusalem reached 102 degrees, during a scorching heat wave. Photo by Debbie Hill/ UPI | License Photo
Living through heat waves is making us age faster, a new study said.
Extreme temperatures are increasingly common because of climate change, potentially causing widespread and long-lasting damage to the health of billions, scientists warned.
Scientists analyzed 15 years of health data from about 25,000 adults in Taiwan and found that two years of exposure to heat waves could speed a person’s so-called biological aging by eight to 12 extra days.
While it seems like a small amount, it builds over time, said Cui Guo, an assistant professor at the University of Hong Kong who led the study, which was published Monday in the journal Nature Climate Change.
“This small number actually matters,” she said. “This was a study of a two-year exposure, but we know heat waves have actually been occurring for decades.”
While we already knew that extreme heat can cause a spike in deaths, this is one of the first to look at heat’s long-term effects.
The researchers found that biological age increased by about nine days for people who experienced four more heat wave days over a two-year period. Manual workers, who tend to spend more time outside, were strongly affected, with their biological age increasing by 33 days.
Right now, the U.S. West Coast is suffering from very high temperatures and Iran has extreme heat. Record-breaking temperatures were seen in Europe, Japan and Korea this month. In 2024, the hottest year on record, climate change caused 41 extra days of extreme heat worldwide, according to World Weather Attribution.
Some groups are more vulnerable to faster aging because of heat, the researchers found. Older people who have lived through many heat waves may age faster than a younger person with the same exposure, Guo said. Living without air conditioning or working outdoors can make the aging rate worse.
But Guo said this isn’t the same as losing days of your life. It’s a measurable shift in biological aging markers.
The study defined heat waves as a period of at least two consecutive days of abnormally high temperatures and any time that officials issued heat warnings. It also considered the sum of a person’s heat exposure.
The study also considered people’s weight, smoking and exercise habits, and any pre-existing conditions like diabetes or cancer.
