New Delhi, Feb 27 – A new genetic study has revealed that prolonged exposure to extreme heat can alter gene expression and potentially accelerate ageing, particularly among older adults.
Researchers from the University of Southern California (USC) found that individuals residing in areas experiencing frequent high temperatures exhibit greater biological ageing than those in cooler regions. Jennifer Ailshire, senior author and professor of gerontology and sociology at USC, explained that older adults are especially vulnerable due to their reduced ability to regulate body temperature through sweating.
"It's really about the combination of heat and humidity. Older adults don't sweat the same way, which diminishes the cooling effect of evaporation," Ailshire noted.
Published in Science Advances, the study analyzed blood samples from over 3,600 adults aged 56 and above over a six-year period (2010-2016). Researchers examined DNA methylation—a process that influences how genes are turned "on" or "off"—to estimate biological ageing. These findings were then compared with historical heat index data from the US National Weather Service.
The participants were part of the Health and Retirement Study (HRS), a long-term research initiative focused on the challenges and opportunities of ageing.
As extreme heat events become more frequent due to climate change, researchers urge governments to implement protective measures, such as improved cooling infrastructure and public awareness programs, to mitigate the health risks associated with heat exposure.
Researchers from the University of Southern California (USC) found that individuals residing in areas experiencing frequent high temperatures exhibit greater biological ageing than those in cooler regions. Jennifer Ailshire, senior author and professor of gerontology and sociology at USC, explained that older adults are especially vulnerable due to their reduced ability to regulate body temperature through sweating.
"It's really about the combination of heat and humidity. Older adults don't sweat the same way, which diminishes the cooling effect of evaporation," Ailshire noted.
How Heat Affects Biological Ageing
Biological age is a measure of the body's functionality at the molecular, cellular, and organ levels. When biological age surpasses chronological age (based on birth date), the risk of various health complications increases.Published in Science Advances, the study analyzed blood samples from over 3,600 adults aged 56 and above over a six-year period (2010-2016). Researchers examined DNA methylation—a process that influences how genes are turned "on" or "off"—to estimate biological ageing. These findings were then compared with historical heat index data from the US National Weather Service.
Key Findings
Co-author Eunyoung Choi, a postdoctoral scholar at USC, highlighted that participants from regions with frequent extreme heat days exhibited significantly higher biological ageing.- Individuals from cities like Phoenix, Arizona, where extreme heat days (above 32°C) occur for half the year, showed up to 14 months of additional biological ageing compared to those living in regions with fewer than 10 extreme heat days annually.
- The correlation between heat exposure and accelerated ageing persisted regardless of socioeconomic status, physical activity, alcohol consumption, or smoking habits.
Implications for Public Health and Policy
The study's authors stressed that their findings could inform public health policies and climate change mitigation strategies, helping to develop targeted interventions for at-risk populations.The participants were part of the Health and Retirement Study (HRS), a long-term research initiative focused on the challenges and opportunities of ageing.
As extreme heat events become more frequent due to climate change, researchers urge governments to implement protective measures, such as improved cooling infrastructure and public awareness programs, to mitigate the health risks associated with heat exposure.
