Heat waves may speed up the aging process »Yale climate connection

Every day, Kalpana Suryawanshi, 48, looks in the mirror and whispers: “I look older than mine.”

Eight years ago, she was diagnosed with type 2 diabetes. Her health has since deteriorated, attributed to working in the fields, growing crops, harvesting produce, and carrying a lot of cattle feed while increasing cattle. During this time, she often felt dizzy and weak due to temperatures exceeding 40 degrees Celsius (104 F) in Nandani village in Maharashtra, India.

Causes are known to affect cognitive function, cardiovascular health, and renal function, and a growing number of studies have shown that exposure to increased temperatures can also accelerate the aging process in the human body. A German study published in the 2023 “Environmental International Environment” is the first to find that higher air temperatures are related to faster aging of cell levels. It found that long-term exposure to temperature increases can make the body age faster than age, a phenomenon called epigenetic age acceleration. Scientists use epigenetic clocks to measure this process, which analyzes chemical markers called DNA methylation, which switches and turns off the gene. The study found that in areas with an average annual temperature of 1°C, people tend to show signs of accelerated aging at the cellular level.

2024 was the hottest year on record, with 6.8 billion people worldwide experiencing extremely high calories in at least 31 days. Community health care workers in India have witnessed an unusual effect of this unusual calories, and they report that they appear to be more people older than they are.

How calories accelerate aging

Now, scientists have also discovered biological mechanisms that lead to premature aging. Wenli Ni, a postdoctoral researcher at Harvard School of Public Health and lead author of the German study, said heat exposure can induce changes in DNA methylation, a biological process that can affect gene expression and cellular function.

She explained that this mechanism can trigger harmful biological processes and accelerate aging. “Carrency exposure can also lead to oxidative stress, which can lead to DNA damage, which changes the DNA methylation pattern and affects aging,” she added. Oxidative damage occurs when unstable molecules are called free radicals attack cells. They can damage DNA, cell membranes, and proteins, leading to aging, cancer and cardiovascular health problems.

These results were repeated in Taiwan, where scientists examined more than 2,000 people and found that altitude temperature and calorie index were associated with an increase in aging and had a greater correlation in prolonged exposure. Studies have shown that an increase in average temperature in 180 days is associated with a 0.04-0.08-year-old acceleration in biological age, measured by estimating three different epigenetic aging clocks for biological age.

Although this increase in age acceleration may seem small at first, it is important to consider how these effects occur over time. Even if it continues year after year, a slight increase in biological aging can accelerate aging. This may mean the early occurrence of age-related diseases. Furthermore, when these small shifts affect large populations, they can lead to a huge increase in the burden of disease and health care costs.

A new study published in Science Advances examines the relationship between calorie and aging in the United States in more than 3,500 adults aged 56 and older. The study found that long-term heat exposure between one and six years is associated with epigenetic aging. Continuous exposure to high temperatures can lead to frequent sleep disorders and increase stress and anxiety levels. Over time, this physiological degradation accumulates and may accelerate healthy declines as you age.

Women are disproportionately affected

The German study found that women and individuals with obese or type 2 diabetes showed a stronger association between air temperature and aging. Ni explained that women often sweat less and respond differently to hot bodies, which may make it harder for them to cool down and sometimes cause their body temperature to be faster.

She also said that studies have shown that women have a higher threshold to activate sweating mechanisms under high temperatures, suggesting that it takes longer for their bodies to start sweating.

Diabetes also makes people more susceptible to high temperatures. Diabetics usually reduce blood flow to their skin, which may interfere with the body's ability to release heat and stay cool during hot weather.

In addition, body fat can act as an insulation, making it harder to transfer heat from the core of the human body to the skin, reducing its ability to release heat and keep it cool.

Accelerated epigenetic age can lead to cardiovascular disease, cancer, diabetes and mortality, putting greater pressure on the public health care system.

In 2016, Rajma Jamadar, 47, from Haroli village in Maharashtra, woke up in the middle of the night with an irregular heartbeat. The next day, the doctor said her blood pressure soared and her lifelong medication was prescribed. Within months, her symptoms worsened as cardiovascular health declined. “Once further diagnosis, the doctor told me that my heart was not drawing blood effectively,” she said.

She prepares meals for 175 children at a public school in her village, but as the heat from cooking is lost, the temperatures make her job harder. “Every day, I feel sick,” she said.

Risks can even begin before birth

It is worth noting that even before birth, climate change may sometimes accelerate epigenetic aging in children. A study published last year in Nature examined controls of 104 children exposed to drought and 109 same-sex siblings in northern Kenya. It found a positive correlation between intralocal drought exposure and aging, highlighting that stressors of drought may reduce overall life expectancy.

According to study author Bilinda Straigh, there are three key pathways in the body that can be changed. The first is the immune system, which is the first line of defense in the human body, which can protect one from infection and disease. The second involves the metabolic process that provides energy to the human body. The third is responsible for maintaining and repairing cells in response to stress.

“Whether the threat we face is physical or emotional, we still see it as a danger to our homeostasis, which is a healthy balance between all our physiological systems,” she explained. This suggests that the emotional stress women experienced in their studies and the activated systems of calorie restriction and dehydration that help the body manage stress, but can harm health if over-activated over a long period of time.

In the study, women also engaged in hunger and dehydration in outdoor labor. “Those physiological stressors are accompanied by concerns about the next meal, themselves, children and loved ones,” she added.

Furthermore, social factors such as gender inequality expose women to coercion, fatigue and violence. Although farmers risk the losses caused by drought, people in livestock farming suffer emotional and economic losses from watching the animals die. Combined with heat stress, dehydration and hunger, this creates great difficulties. Ultimately, this maternal stress during pregnancy can lead to changes in DNA methylation in their children.

She recommends adequate nutrition and close monitoring of children's cardiovascular and metabolic health. Researchers advocate long-term research to better understand the impact of the environment on the accelerated epigenetic age. “The acceleration of slowing down epigenetic age will be related to increasing food security and identifying alternatives to women engaging in high-risk occupations,” she added. Effective policies are needed to achieve food and livelihood security while reducing social and economic inequality.

However, for many women, economic insecurity and lack of social security networks are almost impossible to prioritize health. Suryawanshi's struggle emphasizes this issue. So far, she has spent more than INR 600,000 (US$7,046) on medical care. “I can't afford it, so I've stopped taking medication,” she said. She visited eight hospitals in two years to find effective treatments. “This is a miracle that I survived. Even though I was only 48 years old, I had no strength left, but I still had to work.”