Smoking, drinking, failing to wear sunscreen, eating poorly, not exercising—we all know these unhealthy lifestyle choices can cause us to age prematurely. But new research shows that something basically outside your control could also be a factor. Researchers found that people who live in areas that experience more days of high heat show accelerated biological aging compared to those who live in cooler climates.
RELATED: Doctor Reveals the No. 1 Supplement to Take If You’re Getting Older.
A new study examined local temperatures and aging.
Researchers at the University of Southern California (USC) Leonard Davis School of Gerontology studied the health data of 3,600 U.S. participants aged 56 and older. Over six years, participants’ blood samples were analyzed for “epigenetic changes,” according to a press release.
“Epigenetics refers to how your behaviors and environment can cause changes that affect the way your genes work,” explains the Centers for Disease Control and Prevention (CDC). In other words, it turns genes “on” and “off” through a process called DNA methylation. Some epigenetic changes occur naturally with age, while others result from lifestyle factors.
For the study, which was recently published in the journal Science Advances, researchers used mathematical tools to estimate participants’ biological ages over time.
“Biological age is a measure of how well the body functions at the molecular, cellular, and system levels, as opposed to chronological age based on one’s birthdate,” notes the press release. “Having a biological age greater than one’s chronological age is associated with higher risk for disease and mortality.”
They then compared the biological age data with the National Weather Service Heat Index Chart of each person’s location. The number of high heat days were categorized as follows:
- “Caution” level: heat index values ranging from 80°F to 90°F
- “Extreme Caution” level: between 90°F and 103°F
- “Danger” level: between 103°F and 124°F
More extreme heat days were associated with accelerated biological aging.
After factoring out socioeconomic and demographic differences, as well as lifestyle factors, including physical activity, drinking, and smoking, the researchers found that people living in neighborhoods with more days of extreme heat experienced more significant increases in biological aging.
Study coauthor Eunyoung Choi, USC Leonard Davis PhD in Gerontology alumna and postdoctoral scholar, expanded on this in a statement: “Participants living in areas where heat days, as defined as Extreme Caution or higher levels (≥90°F), 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.”
Jennifer Ailshire, senior author of the study and professor of gerontology and sociology at the USC Leonard Davis School, added that these changes were particularly noticeable in older adults.
“It’s really about the combination of heat and humidity, particularly for older adults, because older adults 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,” she explained. “If you’re in a high humidity place, you don’t get as much of that cooling effect. You have to look at your area’s temperature and your humidity to really understand what your risk might be.”
RELATED: 10 Items You Shouldn’t Wear on Hot Days If You’re Over 65.
Other research linked indoor temperature to cognitive health in older adults.
Geographical temperature may not be the only factor affecting older adults’ health. A separate recent study published in The Journals of Gerontology found that a higher indoor temperature (i.e. cranking up the thermostat) was associated with poorer cognitive health in adults aged 65 and older.
As Best Life reported at the time: “The results showed that sharper cognitive function was associated with older adults whose thermostats were set between 68 and 75 degrees Fahrenheit. Conversely, reports of attention difficulties doubled when temperatures differed by up to seven degrees in either direction.”
The takeaway:
A growing body of research links higher temperatures with poor health outcomes in older adults. The most recent study showed how individuals living in areas with more days of extreme heat (those 90°F and above) exhibited accelerated biological aging.
USC researchers say the next step is determining what may make a person more vulnerable to heat-related aging. They also hope their data will encourage practical lifestyle interventions such as shaded sidewalks and increased urban green space.
