The Heat is On: Extreme Weather May Accelerate Aging in Older Adults, Study Finds
For years, retirement dreams have often included visions of sun-drenched days in warmer climates. However, a new study from the USC Leonard Davis School of Gerontology suggests that this idyllic picture might have a hidden downside. The research indicates that prolonged exposure to extreme heat could accelerate the aging process at a molecular level in older individuals.
The study, published in the esteemed journal Science Advances, reveals that people residing in regions characterized by extended periods of high temperatures appear to experience a faster rate of biological aging compared to those living in cooler areas. This accelerated aging, as demonstrated by the researchers, raises significant concerns about its potential impact on long-term health and well-being.
While chronological age is simply the number of years a person has lived, biological age provides a more nuanced picture of health. According to the National Institute on Aging, biological age reflects how well the body functions at a molecular level. In essence, it gauges the body’s overall health and resilience, irrespective of chronological age. A biological age that surpasses one’s chronological age is often associated with an elevated risk of developing diseases and, ultimately, mortality.
The link between extreme heat, defined as temperatures of 90 degrees Fahrenheit and above, and adverse health outcomes has long been recognized. It is associated with increased risks of heatstroke, dehydration, and even death, particularly among vulnerable populations like the elderly. This new study adds another layer to the understanding of the potential dangers of extreme heat, suggesting it can also accelerate the aging process.
Jennifer Ailshire, a professor of gerontology and sociology at the USC Leonard Davis School and the senior author of the study, collaborated with Eunyoung Choi, a postdoctoral scholar at the same institution, to investigate the relationship between heat exposure and biological aging. Their research focused on a cohort of thousands of U.S. participants aged 56 and older. Over a period of six years, the researchers tracked changes in the participants’ biological age and compared it to their exposure to heat.
Blood samples were collected from the participants at various points throughout the study. These samples were meticulously analyzed for specific changes, known as "epigenetic changes," that affect how individual genes are switched "on" or "off." These epigenetic modifications play a crucial role in regulating gene expression and can be influenced by environmental factors, including temperature.
To analyze these complex epigenetic patterns and estimate biological age, the research team employed sophisticated mathematical tools called "epigenetic clocks." These clocks are designed to assess the degree of age-related changes in an individual’s DNA, providing a quantitative measure of biological age.
The researchers then compared the changes in biological age among the older participants to their respective locations’ heat index history and the number of heat days reported by the National Weather Service from 2010 to 2016. This comprehensive analysis revealed a strong and significant correlation between areas with more days of extreme heat and individuals experiencing greater increases in biological age. This correlation remained even after adjusting for other factors that could influence aging, such as socioeconomic status, lifestyle, and pre-existing health conditions.
"Participants living in areas where heat days — defined as 90 degrees Fahrenheit or higher — occur half the year, such as Phoenix, Arizona, experienced up to 14 months of additional biological aging compared to those living in areas with fewer than 10 heat days per year," explained Choi in a press release. This finding highlights the significant impact that prolonged exposure to extreme heat can have on the aging process.
Importantly, the study considered the heat index, rather than solely relying on air temperature, to account for the impact of relative humidity. Ailshire emphasized the importance of this approach, stating, "It’s really about the combination of heat and humidity. Particularly for older adults, because [they] don’t sweat the same way. We start to lose our ability to have the skin-cooling effect that comes from that evaporation of sweat." This is crucial because high humidity levels can impede the body’s natural cooling mechanisms, making it more difficult for older adults to regulate their body temperature and increasing their risk of heat-related illnesses.
Dr. Chris Scuderi, a family physician based in Jacksonville, Florida, who was not involved in the study, confirmed these concerns based on his clinical observations. "I’ve observed a notable rise in hospitalizations and heat-related incidents among older adults, particularly during last summer’s record-breaking temperatures in Northeast [Florida]," Scuderi told Fox News Digital. This underscores the real-world implications of the study’s findings and highlights the urgent need to address the risks posed by extreme heat to older populations.
Dr. Scuderi also pointed out that certain medications, such as antidepressants and heart medications like beta blockers, can further impair the body’s ability to regulate temperature, thereby increasing the likelihood of heat-related illness. Furthermore, the Centers for Disease Control and Prevention (CDC) emphasizes that certain chronic health conditions can also alter the body’s normal response to heat, making individuals more vulnerable to its harmful effects.
To mitigate the risks associated with extreme heat, Dr. Scuderi offered several practical tips, including scheduling outdoor activities during cooler parts of the day, maintaining proper hydration, and consulting with a family physician to identify any potential medication-related issues. The CDC also recommends drinking water before feeling the sensation of thirst. The CDC also cautions those whose doctors have restricted fluid intake to ask them how much they should drink during hot weather.
Looking ahead, the research team plans to investigate what other factors might make individuals more susceptible to heat-related biological aging and how this accelerated aging might be connected to specific health outcomes. This future research could provide valuable insights into the mechanisms by which heat exposure affects aging and identify potential interventions to protect vulnerable populations.
In the meantime, Ailshire suggested that the study’s findings should prompt policymakers, architects, and urban planners to prioritize heat mitigation and age-friendly designs when updating urban infrastructure. This could involve strategies such as building bus stops with shaded areas, planting more trees to create urban green spaces, and incorporating other features that help reduce heat exposure and promote the well-being of older adults. By taking proactive steps to address the challenges posed by extreme heat, communities can create environments that are healthier and more supportive for people of all ages.
