With her health deteriorating, farmer Kalpana Suryavanshi is constantly worried about how fast she is ageing. (Photo: Sanket Jain)
Every day, 48-year-old Kalpana Suryavanshi looks in the mirror and whispers: “I look older than my age.”
Eight years ago, she was diagnosed with type 2 diabetes. Since then, her health has been deteriorating, which she attributes to increased exposure to heat while working in the fields, planting and harvesting crops, and carrying heavy loads of feed for livestock. At such times, she often feels dizzy and weak when the temperature in her village of Nandani in Maharashtra, India, exceeds 40 degrees Celsius (104 F).
High temperatures are known to affect cognitive function, cardiovascular health, and kidney function, and a growing body of research suggests that exposure to elevated temperatures may also speed up the aging process. A 2023 German study published in the journal Environment International is the first to find a link between higher air temperatures and accelerated aging at the cellular level. It found that long-term exposure to high temperatures can cause the body to age faster than its chronological age, a phenomenon known as epigenetic acceleration of aging. Scientists measure this process using epigenetic clocks that analyze chemical markers known as DNA methylation, which activate or deactivate genes. The study found that in regions where the average annual temperature is 1°C higher, people tend to show signs of accelerated aging at the cellular level.
What is epigenetic age?
When scientists discuss epigenetic age, they are referring to an organism's age at the cellular level, which can differ from its actual age in years. It is based on changes in DNA called epigenetic markers, chemical tags that activate or deactivate genes.
Environment, lifestyle, and stress all influence these markers. As we age, the structure of these chemical tags changes, and scientists use this information to create an epigenetic clock, a tool that estimates biological age.
The genes affected by these changes control many vital functions, such as repairing cells and tissues and protecting against toxins. When abnormal genes are activated or deactivated, it becomes more difficult for the body to repair itself, fight disease, or recover from stress. Over time, these hidden changes can lead to outward signs of aging, such as weakened bones or slower healing.
Epigenetic age provides insight into how well the body is coping from the inside out.
2024 was the hottest year on record, with 6.8 billion people worldwide experiencing extreme heat for at least 31 days. One interesting effect of this rising heat is being noted by health officials in India, who report that more people are looking older than their actual age.
How Heat Can Speed Up Aging
Scientists are also finding biological mechanisms that contribute to premature aging. Wenli Ni, a research fellow at the Harvard T.H. Chan School of Public Health and lead author of the German study, said heat exposure can cause changes in DNA methylation, a biological process that can affect gene expression and cellular function.
She explained that this mechanism can activate harmful biological processes and accelerate aging. “Heat exposure can also lead to oxidative stress, which causes DNA damage, which can alter DNA methylation patterns and affect aging,” she added. Oxidative damage occurs when unstable molecules called free radicals attack cells. They can damage DNA, cell membranes, and proteins, contributing to aging, cancer, and cardiovascular health problems.
These results were confirmed in Taiwan, where scientists examined more than 200
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