We all know that extreme heat can be uncomfortable, draining, and even dangerous. However, new research suggests extreme heat exposure might also speed up the aging process. Scientists have found that prolonged exposure to high temperatures may accelerate biological aging, increasing the risk of age-related diseases and other health issues.
A recent study led by researchers at the University of Southern California examined how extreme heat changes how we age at the biological level. Using epigenetic clocks, a method that tracks chemical changes in DNA linked to aging, scientists analyzed blood samples from 3,600 older adults across the US.
They discovered that for every 200 days spent in temperatures of 32.2 degrees Celsius (90 degrees Fahrenheit) or higher over a six-year period, participants’ biological age increased by up to 3.5 months compared to those in cooler regions. In other words, individuals exposed to excessive heat for prolonged periods were aging at an accelerated rate at the cellular level.
Our bodies respond to heat stress in various ways. From dehydration to increased inflammation and even oxidative stress—all of these contribute to cellular damage. This damage affects DNA methylation, which is a key process in epigenetic aging that influences how genes function over time.
The new study suggests that extreme heat may alter DNA activity in ways that make the body biologically older than its actual age. The effects heat has on biological aging may not be universal, either. Factors like access to air conditioning, time spent outdoors, and lifestyle choices can influence individual risk.
While the study controlled for age, race, wealth, obesity, smoking, and alcohol use, the researchers did not directly account for cooling methods or personal heat exposure habits. Additionally, while they focused on older adults, experts believe younger populations may be affected, too. However, more research is needed to confirm whether heat exposure accelerates aging across all age groups.
