Long-term exposure to extreme heat may accelerate the body’s ageing process in ways comparable to smoking or alcohol consumption, according to new research published in Nature Climate Change.
The study, which tracked 24,922 people in Taiwan between 2008 and 2022, found that repeated heatwave exposure increases a person’s biological age — the measure of how well organs and tissues are functioning — beyond their actual chronological years. Researchers calculated biological age using medical markers such as blood pressure, organ function, and inflammation levels, then compared them with cumulative temperature exposure in the years leading up to participants’ health checks.
The findings reveal that for every 1.3 °C increase in long-term heat exposure, people added an average of 0.023–0.031 years to their biological age. Though seemingly small, researchers emphasize that such effects can build up across lifetimes and populations, creating serious public health implications.
“This study is a wake-up call that we are all vulnerable to the adverse impacts of climate change on our health,” said Paul Beggs, an environmental-health scientist at Macquarie University in Sydney, who was not involved in the research. “The fact that heatwaves age us is surprising, and it reinforces the need for urgent reductions in greenhouse-gas emissions.”
The researchers found that manual workers and rural populations faced the greatest risks, likely due to reduced access to air conditioning and other cooling technologies. However, the negative impact of heat on ageing appeared to decline over the 15-year study period, suggesting possible adaptation — perhaps due to wider availability of cooling measures.
Previous studies in Germany and the United States have similarly linked heat exposure to accelerated ageing, including changes at the DNA level. With climate change driving a surge in extreme-heat events — in the U.S. alone, the average number of heatwaves per year has tripled since the 1960s — scientists warn that the health burden could rise sharply in the coming decades.
“Heatwaves are not just uncomfortable weather events; they can silently speed up the ageing of our bodies,” said Cui Guo, lead author of the study and an environmental epidemiologist at the University of Hong Kong. “This is not only a personal health risk, but a global concern.”
