Long-term impacts of heatwaves on accelerated ageing

Climate change and population ageing are both urgent global challenges. Yet the interaction between these, such as associations between long-term exposure to heatwaves and biological age acceleration (BAA), is unclear. Here we analysed data from 24,922 adults in a longitudinal cohort in Taiwan (2008–2022) and used linear mixed models to show heatwaves accelerate ageing. Heatwaves were defined using both relative and absolute thresholds. BAA was calculated as the difference between biological and chronological age. Each interquartile range increase in the cumulative exposure to heatwaves was associated with a 0.023- to 0.031-year increase in BAA. Moreover, the participants demonstrated gradual adaptation to heatwave impacts over the 15-year period. Furthermore, manual workers, rural residents and participants from communities with fewer air conditioners were more susceptible to the health impacts. This study highlights the need for targeted policies and interventions to strengthen adaptive capacity, delay ageing and promote healthy ageing. Ageing is linked to environmental factors. This study shows that although participants gradually adapted to heat over time, cumulative exposure to heatwaves had stable and adverse impacts on ageing, especially among manual workers, rural residents and those with limited air conditioning.