Repeated Heat Waves Can Age You as Much as Smoking or Drinking
A new long-term study suggests that the more heat waves people are exposed to, the more their body’s aging process accelerates
An elderly man is seen resting under a tree at Levico lake. With temperatures exceeding 45 degrees Celsius in many parts of Italy, and wildfires burning in France, Spain and Portugal, Europe is under under alert as the heatwave grips the continent.
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Long-term exposure to extreme heat events accelerates the body’s ageing process and increases vulnerabilities to heath issues, finds a long-term study of 24,922 people in Taiwan.
The study, published today in Nature Climate Change, suggests that moderate increases in cumulative heatwave exposure increase a person’s biological age — to an extent comparable to regular smoking or alcohol consumption. The more extreme-heat events that people were exposed to, the more their organs aged. This is the latest study to show that extreme heat can have invisible effects on the human body and accelerate the biological clock.
Exposure to extreme heat, especially over long periods of time, strains organs and can be lethal, but “the fact that heatwaves age us is surprising”, says Paul Beggs, an environmental-health scientist at Macquarie University in Sydney, Australia, who was not involved in the research. “This study is a wake-up call that we are all vulnerable to the adverse impacts of climate change on our health. It reinforces calls for urgent and deep reduction in greenhouse-gas emissions,” he adds.
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In 2023, research in Germany found that higher air temperatures were associated with more epigenetic markers of ageing. And a study in more than 3,600 older people in the United States similarly concluded, through analysing DNA markers, that extreme heat prematurely aged participants.
The most recent study focused on the impact of long-term heat exposure, which is more likely to have lifelong health effects. This is important because climate change is leading to more extreme-heat events. In the United States, there are now six heatwaves each year, as of 2010 — up from two in the 1960s. Scientists estimate that climate change has made heatwaves such as the deadly 2022 ones in Pakistan and India, during which temperatures hit 50 °C, 30 times more likely to occur.
The growing frequency of heatwaves, combined with their effects on health, highlights the importance of protecting vulnerable groups, says Guo. “Heatwave is not a personal risk factor, but a global concern.”
This article is reproduced with permission and was first published on August 26, 2025.
Freda Kreier is a freelance journalist who likes writing about the natural world, DNA and the distant past. You can find more of her work at www.fredakreier.com.
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