Repeated exposure to heatwaves is accelerating the biological ageing of people, according to a new study. The impact is broadly comparable with the damage caused by smoking, alcohol use, poor diet or limited exercise, researchers said.
The findings come as extreme temperatures become more frequent due to the climate crisis. Scientists warn that billions of people could face long-lasting health damage. The research, published in Nature Climate Change, followed 25,000 adults in Taiwan for 15 years and compared their exposure to heatwaves with their biological age – a measure of overall health based on medical tests.
The study found that biological age increased by about nine days for people who experienced four more heatwave days over a two-year period. Manual workers, who tend to spend more time outside, were more strongly affected, with their biological age increasing by 33 days over the same period.
Dr Cui Guo of the University of Hong Kong, who led the research, said: “If heatwave exposure accumulates for several decades, the health impact will be much greater than we have reported.” He added that heatwaves are becoming more frequent and lasting longer.
Professor Paul Beggs of Macquarie University in Sydney, who was not involved in the study, described the research as a “paradigm shift” in understanding the extent and severity of heat’s impact on health. “The impact can occur at any age and can be lifelong,” he said.
The researchers noted that the study’s participants were on average healthier and more educated than the general population, meaning the real-world impact on ageing is likely to be larger. The exact mechanism behind heatwave-driven ageing is unclear, but DNA damage is thought to play a role.
