WHERE you live can affect how fast your body ages, a study has revealed.
American scientists tracked how thousands of people’s biological ages changed over time – finding that the weather can slow down or speed up the process.
Living in spots hit by heatwaves can make your body age faster[/caption]
People living in spots hit by more hot weather aged faster at a molecular level than residents of cooler regions, researchers from University of Southern California USC Leonard Davis School of Gerontology revealed.
Their findings suggest greater exposure to extreme heat may accelerate biological ageing in older people, raising concerns about how climate change and heatwaves could affect long-term health.
Senior study author Professor Jennifer Ailshire explained that biological age is a measure of how well the body’s molecules cells and systems function, as opposed to the number based on your birthday.
It may be a better indicator than chronological age of how long you will live and be in good health for.
Having a biological age greater than one’s chronological age is has been linked to a higher risk for disease and death.
Exposure to extreme heat – anything above 32.2 Celsius 90 Fahrenheit – has long been associated with health issues, including increased risk of death.
But Prof Ailshire said heat’s link to biological ageing has been unclear up till now.
Prof Ailshire and her co-author Dr Eunyoung Choi examined how biological age changed in more than 3,600 people aged 56 and older across the United States.
Blood samples taken at various times during the six-year study period were analysed for epigenetic changes.
This refers to how behaviours or the environment can cause changes that affect how your genes work.
Individual genes can be turned “off” or “on” by a process called DNA methylation.
The research team used mathematical tools called epigenetic clocks to analyse methylation patterns and estimate biological ages at each time point.
They then compared participants’ changes in biological age to their location’s heat index history and number of heat days reported by the National Weather Service from 2010 to 2016.
The National Weather Service Heat Index Chart categorises heat index values into three levels, based on the potential risk of adverse health effects:
- “Caution” level – heat index values ranging from 80F (26.6C) to 90F
- “Extreme Caution” level – values between 90F and 103F (39.4C)
- “Danger” level – values between 103F and 124F (51.1C)
All three levels were recorded in the time period of the study.
People living in Phoenix, Arizona, experienced higher rates of biological ageing[/caption]
The analysis, published in the journal Science Advances, revealed a “significant correlation” between areas with more days of extreme heat and people experiencing greater increases in biological age.
The link still applied after taking into account socio-economic and other demographic differences, as well as lifestyle factors such as physical activity, alcohol consumption and smoking.
Tips to age well
There are a number of habits you can take up to care for your health and wellbeing as you age.
Age UK shared the following tips:
- Do things that you enjoy everyday – whether that’s cooking, seeing friends or enjoying a good book
- Stay hydrated – drink six to eight cups of water a day
- Eat plenty of fruit and veggies to lower your risk of heart disease and certain cancers, have beans, pulses, fish, eggs and meat to repair your body after injury, starchy carbs for energy dairy to help keep bones strong
- Manage long-term health conditions to prevent them progressing or having a greater impact on your health
- Quit smoking and reduce alcohol intake to no more than 14 units a week
- Make mental health a priority and get treatment for it, as it can also impact physical health
- Make sure you’re getting quality sleep
- Keep socialising – and call a friend or loved one if you can’t make it out the house
- Be physically active to lower the risk of depression and dementia, heart disease, stroke, Parkinson’s and some cancers
Dr Choi said: “Participants living in areas where heat days, as defined as Extreme Caution or higher levels, occur half the year, such as Phoenix, Arizona, experienced up to 14 months of additional biological ageing compared to those living in areas with fewer than 10 heat days per year.
“Even after controlling for several factors, we found this association.
“Just because you live in an area with more heat days, you’re ageing faster biologically.”
She said all three epigenetic clocks employed in the study revealed this association.
Heat-related epigenetic changes can happen in a matter of days after a hot period, while others may accumulate over time, researchers found.
Prof Ailshire says older people are “particularly vulnerable” to the effects of high heat.
She noted that the study used heat index, rather than just air temperature, to take relative humidity into account as they analysed results.
Prof Ailshire said: “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.
“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.”
She said the next steps for the research team will be to determine what other factors might make someone more vulnerable to heat-related biological ageing and how it might connect to health.
Prof Ailshire says that, in the meantime, the findings could also prompt policymakers, architects, and others to keep heat mitigation and age-friendly features in mind as they update urban infrastructure.
This may include building bus stops with shade in mind or planting more trees and increasing green spaces in urban environments.
She added: “If everywhere is getting warmer and the population is ageing, and these people are vulnerable, then we need to get really a lot smarter about these mitigation strategies.”
