A study has revealed that repeated exposure to heatwaves causes a person's biological age to increase faster than their chronological age. The research team pointed out that the impact of heatwaves on biological aging is comparable to the harmful health effects of smoking, drinking, an unbalanced diet, and lack of exercise. They warned that with the climate crisis making extreme high-temperature events more frequent and prolonged, human health could be under long-term threat.
A research team led by Professor Guo Cui of the University of Hong Kong published findings in the international journal 'Nature Climate Change' on the 25th (local time), showing that heatwave exposure accelerates biological aging, based on a 15-year observation of 25,000 Taiwanese adults.
It is well-known that heatwaves increase premature deaths in the short term. A prime example is the heatwave in the United Kingdom last June, which led to approximately 600 premature deaths. This study is noteworthy as it is the first to comprehensively track the rate of aging due to long-term exposure.
The results showed that for every four-day increase in heatwave days over a two-year period, biological age accelerated by an average of nine days. Under the same conditions, outdoor workers experienced an acceleration of their biological age by 33 days. Biological age is calculated based on health indicators such as blood pressure, inflammation levels, cholesterol, and lung, liver, and kidney function. It is used as an indicator that better reflects overall health status than chronological age.
The study participants were all young, healthy, and highly educated adults enrolled in a private healthcare program. The research team anticipates that the aging effect would be even greater in the general population, as the elderly and individuals with underlying health conditions are more vulnerable to heatwaves.
The team added that while factors such as weight, smoking and exercise habits, pre-existing conditions like diabetes or cancer, and the prevalence of air conditioning in residential areas were considered, variables like individual living environments or time spent outdoors were not included, necessitating further research.
Professor Guo, who led the study, stated, “If exposure to heatwaves accumulates over decades, the health damage will be far greater than what has been reported in this study.”
Why heatwaves accelerate aging has not been clearly identified. DNA damage is suggested as a potential key factor. In this study, the negative effects of heatwaves tended to diminish somewhat over time but still had a significant impact on health.
Paul Backx, a professor at Macquarie University in Australia who was not involved in the study, commented in an interview with the British daily The Guardian, “Many people thought they came through heatwaves unscathed, but in reality, that's not the case,” and assessed that “it has been confirmed that exposure to heatwaves alters the speed at which we age.”
He also noted, “In 2024, a study was also published showing that childhood exposure to heatwaves harms the development of brain white matter,” and pointed out, “The impact of heatwaves can occur across the entire lifespan, accelerating aging in adults and hindering brain development in children.”
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- doi.org/10.1038/s41558-025-02407-w
