Sleep scientists just calculated how much shut-eye you really need as you age—and it’s not 8 hours

One of the most important things for your health is something most people don’t get enough of—sleep. And while doctors have traditionally equated getting eight hours with a good night’s rest, new research suggests something different. A new sleep study, published in the journal Nature on May 13, finds for those in middle age and older, the “sweet spot” is somewhere between 6.4 and 7.8 hours. “Our study . . . shows that too little and too much sleep are associated with faster aging in nearly every organ,” the study’s lead author Junhao Wen, assistant professor of radiology at Columbia University Vagelos College of Physicians and Surgeons, said in a statement. In other words, too few or too many hours of sleep “may speed aging in the brain, heart, lung, and immune system—and is associated with a wide range of diseases.” Researchers, led by scientists at Columbia University, found “short sleep” was significantly associated with depressive episodes, anxiety disorders, type 2 diabetes, heart disease, and obesity. Meanwhile, those getting both “short and long sleep” were more associated with diseases like asthma and digestive disorders like gastritis. Using data from a U.K. Biobank study of 500,000 volunteers, researchers applied machine learning to determine how aging in various organs and parts of the body was linked to length of sleep. Since organs age at different rates, Wen’s ability to create “aging clocks” for specific organs in the body puts his team at the forefront of aging research. “Everyone is excited by these ‘aging clocks’ and their ability to predict disease and mortality risk,” Wen said. “But to me, the more exciting question is, can we link aging clocks to a lifestyle factor that can be modified in time to slow aging?”