A new study by researchers at the University of Southern California (USC) has found that living in areas with long periods of extreme heat could be quietly speeding up how our bodies age — not on the outside, but at the cellular level. This means the heat may be increasing the risk of chronic illnesses and early physical decline without people even noticing.The Hidden Risk in Warm Retirement StatesOver the past few years, many older Americans have moved to sunny states like Florida, Texas, and North Carolina for their pleasant weather and low taxes. But these so-called “retirement havens” are also some of the hottest parts of the U.S. — and that’s where the danger lies.Dr. Eun Young Choi and her team studied data from 3,686 people aged 56 and older between 2010 and 2016. They discovered that the more days people were exposed to extreme heat, the faster their biological age increased. The results were published in the journal Science Advances.What Is Biological Aging?Biological aging is not the same as the number of years you’ve lived. It’s about how old your body feels and functions at the cellular level. This can tell us how vulnerable someone might be to diseases or health problems. For example, two 60-year-olds may be the same age on paper, but the one with more heat exposure may have a body that behaves like it's 63.How the Study Measured AgingThe USC researchers used three high-tech “aging clocks” to track the body’s internal changes:PCPhenoAge predicts health problems in the future.PCGrimAge estimates risk of death.DunedinPACE tracks how quickly the body is aging.Their analysis showed that people exposed to more than 140 days of extreme heat in a year had biological ages up to 14 months older than their actual age. Over six years, those living in hot zones saw their biological age increase by nearly 3 years.Why This Matters“Heat exposure isn’t just about feeling uncomfortable or getting sunburned,” said Dr. Choi to Daily Mail. “It puts long-term stress on the body, which can lead to serious health problems.” Previous studies have already linked faster biological aging with a higher risk of heart disease, diabetes, memory loss, and even early death.States like Louisiana, Mississippi, Texas, Alabama, and Arkansas were among the worst hit. In some places, people lived in “danger-level” temperatures — over 103°F — for years.Cooling Access Makes a DifferenceDr. Choi pointed out that not everyone in a hot state is equally at risk. Things like having air conditioning, access to cooling centers, or whether someone works outdoors can make a big difference — even between two people living on the same street.Is Any Heat Good?Interestingly, not all heat is harmful. “Short bursts of heat, like saunas or hot showers, may actually help circulation and heart health,” Dr. Choi said. But for everyday life, especially for older adults or people with health conditions, staying cool and hydrated is key.The takeaway? As climate change makes heat waves more common, protecting our bodies from constant high temperatures could be just as important as eating healthy or quitting smoking.