Category: Research I Ageing and Longevity
Written By: Team Pharmacally
Medically Reviewed By:
Dr. Swati Deore-Pawar, Cosmetologist (BAMS, ACCR, PGDCC)
Ageing is a natural process in which the body gradually loses physiological strength, leading to slower repair mechanisms, reduced organ function, and greater vulnerability to disease. Scientists describe this decline using two different measures. Chronological age is simply the number of years a person has lived. It is fixed and moves at the same rate for everyone. Biological age, in contrast, reflects how “old” the body actually functions, based on clinical markers such as blood pressure, kidney and liver function, inflammation, and cellular stress. Two people of the same chronological age may have very different biological ages, depending on genetics, lifestyle, and environmental exposures. Smoking and heavy alcohol uses are well-known factors that accelerate biological ageing, but until recently, the impact of environmental stressors like repeated heatwaves had received much less attention.
A recent study published in Nature Climate Change in August 2025 shows that repeated exposure to heatwaves can accelerate biological ageing which push the body to function older than its actual chronological years. The researchers found that this effect of heatwaves is similar to the impact of smoking or regular alcohol use, placing environmental heat stress together with lifestyle risk factors. This findings place climate change not only as an ecological challenge but also an age-related health decline.
Study Design and Methods Cohort
The study was conducted on a cohort of 24,922 adults in Taiwan who were followed from 2008 to 2022. Participants underwent repeated health check-ups to monitor changes in ageing over time. At each visit, detailed clinical and physiological data were collected, including blood pressure, blood tests, and markers of different organ functions like liver function and kidney function, which were then used to estimate biological age. Heatwave exposure was assessed using both absolute temperature thresholds, reflecting extreme heat levels, and relative thresholds, capturing unusually high temperatures for a given area, based on meteorological data from participants’ residential locations. To measure the impact of heat, researchers applied validated biomarker-based algorithms to calculate Biological Age Acceleration (BAA) the difference between an individual’s biological and chronological age where a positive BAA suggested faster-than-expected ageing. Statistical analysis used as linear mixed-effects models, adjusting for factors such as age, sex, occupation, and socioeconomic status. Subgroup studies compared outcomes among manual versus non-manual workers, urban versus rural residents, and communities with differences in access to air conditioning.
Results
The study found a strong connection between repeated heatwave exposure and faster biological ageing. People exposed to more heatwaves, aged about 8 to11 extra days beyond their actual age over two years. Outdoor manual workers were the most affected, showing up to 33 extra days of ageing, while rural residents and those with limited access to air conditioning were also at higher risk. These results shows how jobs and living conditions can influence heat-related health risks. Over the 15-year follow-up, the effect became weaker because people slowly adapted to conditions by using more cooling systems, changing daily routines to avoid extreme heat, and becoming more aware of heat dangers.
Comparison with Smoking and Alcohol Consumption
The detected ageing effect size from repeated heatwave exposure is similar to lifestyle risks such as regular smoking and chronic alcohol use. While smoking is known to accelerate ageing by 1–2 years depending on intensity, the Data from Taiwanese study suggest that repeated heat exposure can speed up ageing across the population, with the strongest effects seen in people most exposed. This shows that heat stress from climate change is a preventable risk for premature ageing, similar to lifestyle factors like smoking or alcohol use.
Biological Mechanisms
Several biological pathways can be linked with observed association between heatwave exposure and accelerated ageing. Out of these, some are explained below; 1) ROS: Repeated heat stress increases the production of reactive oxygen species (ROS), leading to oxidative damage of DNA, proteins, and lipids. 2) Inflammatory Response: Heat can trigger systemic inflammatory responses, which are well-recognized contributors to age-related diseases. 3) CVS and Metabolic Effect: Prolonged exposure also places strain on cardiovascular and metabolic systems, with risks of dehydration, electrolyte imbalance, and faster functional decline in organs such as the heart, kidneys, and liver. In addition, earlier studies suggest that heat may influence epigenetic regulation, including alterations in DNA methylation patterns, which aligns with the acceleration of “epigenetic clocks” commonly used in ageing research.
Public Health Implications
The findings carry important public health implications. Outdoor workers are remains to be high-risk group, stressing the need for occupational precautions such as planned work–rest cycles, hydration support, and shaded recovery spaces. Making air conditioning more affordable and setting up community cooling centers could protect rural and low-income groups from the unequal impacts of heat. Policies on heat and health should address the long-term ageing effects of heat exposure, not just immediate outcomes like deaths. Future research should test these results in different climates, use genetic ageing markers, and see if specific interventions can slow or even reverse heat-related ageing.
Conclusion
Long-term exposure to repeated heatwaves is associated with accelerated biological ageing, with an effect size comparable to lifestyle risk factors such as smoking and alcohol consumption. The findings highlight the need for urgent climate-adaptation strategies, particularly for vulnerable subgroups, as global temperatures continue to rise. Protecting populations from chronic heat exposure should be recognized as a critical component of healthy ageing policies in the 21st century.
References
Chen, S., Liu, Y., Yi, Y. et al. Long-term impacts of heatwaves on accelerated ageing. Nat. Clim. Chang. (2025). https://doi.org/10.1038/s41558-025-02407-w
Kreier F. Repeated heatwaves can age you as much as smoking or drinking. Nature news, August 26, 2025. https://www.nature.com/articles/d41586-025-02729-x
Heatwaves are making people age faster, study suggests. The Guardian, August 25, 2025. https://www.theguardian.com/environment/2025/aug/25/heatwaves-making-people-age-faster-study-suggests