A new study warns that extreme heat may influence biological ageing more than smoking or drinking alcohol, especially in older adults. As global temperatures rise due to climate change, scientists are discovering that heat could accelerate the ageing process, putting seniors at greater risk for health issues.
The research, published in Science Advances, shows how exposure to high temperatures can increase biological ageing in older individuals. Biological ageing refers to the wear and tear of cells and tissues, which can lead to various diseases and premature death. Researchers suggest that prolonged exposure to extreme heat may be a significant factor in how quickly people age biologically.
The Study: Heat and Its Effects on Ageing
The study was conducted by researchers from the University of Southern California (USC), who analyzed data from over 3,600 adults aged 56 and older in the United States. The scientists focused on biological markers from participants, comparing them with the temperature patterns in the areas where they lived.
The findings were striking. People who lived in areas where temperatures often exceeded 32°C (90°F) – classified as “Extreme Caution” or higher by the US National Weather Service – showed signs of accelerated biological ageing. In some cases, their biological age was up to a year ahead of their chronological age.
Unlike chronological age, which simply tracks the years since birth, biological age refers to how well or poorly someone’s body is functioning. A person’s biological age can be younger or older than their actual age, and a higher biological age increases the risk of illness and early death.
Researchers used a method called epigenetic clocks to measure biological age. These clocks track DNA changes over time. Blood samples taken from participants between 2010 and 2016 were analyzed, and researchers compared the results with the local temperature and heat index, which includes both temperature and humidity.
The researchers found that those living in hotter areas experienced faster biological ageing, even after considering lifestyle factors like smoking, alcohol use, and exercise. This shows that heat itself plays a significant role in accelerating the biological ageing process.
The Role of Heat and Humidity in Accelerating Ageing
While high temperatures alone are harmful, humidity can make the effects of heat even worse. When humidity is high, the body has a harder time cooling down because sweat evaporation slows down. This is particularly dangerous for older adults, who often have a reduced ability to sweat.
Jennifer Ailshire, a gerontology professor at USC and one of the study’s authors, explains that the combination of heat and humidity is especially problematic for seniors. “Older adults don’t sweat the same way as younger people, so they are more vulnerable to heat stress,” she says. “It’s not just about temperature; humidity is a key factor in how the body reacts to heat.”
Climate Change and Its Impact on Health
As global temperatures rise due to climate change, the effects on vulnerable populations are becoming more pronounced. The World Meteorological Organization (WMO) recently reported that 2024 was the warmest year on record, with temperatures about 1.6°C higher than pre-industrial levels. Heatwaves are becoming more frequent, and they’re expected to worsen as the planet continues to warm.
Previous studies have linked extreme heat to various health problems, including cardiovascular issues, kidney damage, and cognitive decline. According to the World Health Organization (WHO), heat-related illnesses cause over 175,000 deaths annually in Europe. By 2099, climate change could lead to an additional 2.3 million deaths across the continent.
This new study suggests that older adults could be at an even greater risk than previously thought. As the global population continues to age, the impact of heat on seniors could become a serious public health issue.
Mitigating the Effects of Extreme Heat
To protect vulnerable populations from the dangers of extreme heat, researchers stress the need for effective mitigation strategies. Ailshire emphasizes that cities must adapt to the changing climate by implementing heat-resilient infrastructure and expanding green spaces. Urban areas can help reduce the effects of heat by planting more trees, building cooler surfaces, and creating more green spaces that offer shade and lower temperatures.
Without such measures, the growing frequency and intensity of heatwaves could lead to even more severe health consequences for older populations in the coming decades.
As the climate crisis continues to unfold, extreme heat could become a major factor in accelerating the biological ageing process, particularly for older adults. While the study highlights the need for action, it also stresses the importance of a comprehensive approach to addressing climate change, protecting vulnerable groups, and making our cities more resilient to rising temperatures.
These findings serve as a wake-up call for governments, urban planners, and public health officials to work together in developing strategies to protect senior citizens from heat-related health risks. As our world heats up, protecting our ageing population from the harmful effects of extreme heat will become more crucial than ever.
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