Everyone has felt the exhaustion and dehydration that comes with spending too much time in the heat. But research shows that the impact of being exposed to extreme heat goes beyond heat waves: consistent exposure to high temperatures might also be making you age more quickly.
A new study, published Aug. 26 in the journal Nature Climate Change, found that repeated exposure to heat waves was linked to accelerated aging and increases vulnerability to health issues. The more extreme heat events an individual was exposed to, the more their bodies aged.
Researchers analyzed medical data from nearly 25,000 people in Taiwan over the course of 15 years: between 2008 and 2022, when the region experienced 30 heat waves (defined by the researchers as a “period of elevated temperature over several days”). They were able to calculate a person’s biological age by using results from several medical tests including assessments of liver, lung, and kidney function; blood pressure; and inflammation. They then used participants’ addresses in the two years before their medical visit to compare their biological ages to the temperatures that they were likely exposed to.
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They found that the more extreme heat events a person endured, the more quickly they aged, with every extra 1.3°C of total cumulative heat adding around eight to twelve days to their biological age. Manual laborers and those living in rural areas experienced the largest health impacts.
“While the number itself may look small, over time and across populations, this effect can have meaningful public-health implications,” Cui Guo, the lead study author and an environmental epidemiologist at the University of Hong Kong, told Nature.Â
Climate change is making extreme heat events more common around the world. 2024 was the hottest year on record, topping the record set in 2023. A Climate Central study found that 88% of 247 major U.S. cities have seen an increase in the number of extremely hot days since 1970.
Climate models show that global temperatures will only continue to rise, with the World Meteorological Organization estimating a 70% chance that the five-year average warming for 2025 to 2029 will be more than 1.5 °C. Creating solutions to combat extreme heat is only going to become more imperative as temperatures increase, experts say.
