Can Heatwaves Make You Age Faster?

A recent study published in Science Advances suggests that prolonged exposure to high outdoor temperatures could accelerate biological aging, raising concerns about the long-term health risks of climate change. The research found that extreme heat/heatwaves may trigger changes in DNA methylation (DNAm), a key biomarker of aging, potentially increasing the risk of age-related diseases.

Heatwave Exposure and Its Effect on Aging

With global temperatures rising, the frequency and intensity of heatwaves have increased, particularly affecting older adults. While extreme heat is known to cause heatstroke, dehydration, and cardiovascular stress, its impact on long-term biological aging has been unclear.

Previous animal studies suggested that heat stress could induce maladaptive epigenetic memory, leading to persistent changes in DNA structure and gene expression. However, this study provides new human data supporting the idea that prolonged heat exposure accelerates epigenetic aging, which can increase the risk of morbidity and mortality.

Study Overview

Researchers analyzed blood samples from a nationally representative cohort of older adults in the U.S., tracking epigenetic aging markers in relation to their ambient heat exposure. They measured heat index (HI)—a combination of temperature and humidity—to assess real-world heat exposure.

The study examined three epigenetic aging markers:

• PhenoAge (biological age predictor)
• GrimAge (age-related mortality predictor)
• DunedinPACE (pace of aging measure)

Key Findings:

• Short-term exposure (1 day) to caution-level heat was associated with a 1.07-year increase in biological age.
• One-week exposure increased biological age by 1.15 years, while longer-term exposure (six years) led to even greater aging acceleration.
• DunedinPACE and GrimAge showed significant increases in aging rate after long-term exposure to extreme heat.

Interestingly, the study found no major differences in heat sensitivity across sociodemographic groups, suggesting that all older adults are at risk.

Implications for Public Health and Climate Change

These findings highlight climate change’s potential to accelerate aging and increase disease risk, reinforcing the need for stronger public health measures to protect vulnerable populations.

Possible mitigation strategies include:

• Increased cooling infrastructure (air conditioning, cooling centers)
• Improved urban planning to reduce heat islands
• Public health interventions for older adults and those with chronic conditions
• Further research on biological resilience against extreme heat

Conclusions

This study underscores the urgent need to address rising temperatures as a major public health threat. With climate change driving more extreme weather, identifying biological pathways affected by heat exposure could help develop preventive measures to slow aging and improve long-term health outcomes.

More Information: Choi, E. Y. & Ailshire, A.J. (2025) Ambient outdoor heat and accelerated epigenetic aging among older adults in the US. Science Advances 11(9). doi:10.1126/sciadv.adr0616