No one likes a heatwave, and a new study has found another reason to hate it. Repeated exposure to extreme heatwaves may be quietly speeding up the ageing process in people.
According to the study published in the journal Nature Climate Change, the side effects of heatwave exposure are comparable to smoking, alcohol use, poor diet, or lack of exercise.
The Study
Researchers analysed data from 25,000 adults in Taiwan for 15 years and monitored their exposure to heatwaves alongside detailed health records. They measured each person's biological age - an assessment of overall health based on medical tests, including their blood pressure levels, cholesterol, inflammation, and organ function and then they compared it to their actual age.
The results showed that people exposed to four additional heatwave days over a two-year period aged biologically by around nine days. As per the study, manual workers who spend more time outdoors were hit the hardest, showing an increase in biological age of 33 days over the same period.
The researchers pointed out that the study only observed the subjects for two years, but the cumulative impact of decades of heatwave exposure could be more severe.
Why It Matters
Previous research, including the one published in the journal Environment International, found a link between exposure to high temperature and daily mortality. However, the researcher says that this study is among the first to reveal long-term health consequences, suggesting heatwaves don't just kill suddenly but may also silently affect your health over time.
How Does Heat Accelerate Ageing
The exact biological mechanism is not fully understood, but researchers suggest that DNA damage may be part of the reason. Prolonged exposure to high temperatures may increase oxidative stress, inflammation, and strain on vital organs.
Although some harmful effects appeared to reduce over time - perhaps because people adapted by seeking shade or using air conditioning - the damage remained significant. Importantly, the study participants were younger, healthier, and more educated than the general population, meaning real-world impacts could be much worse, especially for older or vulnerable groups.
The researchers concluded that exposure to outdoor heat accelerated ageing among older adults and contributes to faster cognitive decline, particularly among Black communities and residents of poorer neighbourhoods.
According to the study, heatwaves are no longer just a short-term inconvenience, but a slow, silent driver of premature ageing.