Sleep quality seems to improve during a lifetime, challenging the conventional wisdom that trouble sleeping is a part of aging, UPI cited U.S. researchers as suggesting. Lead author Michael Grandner, research associate at the Center for Sleep and Circadian Neurobiology at the Perlman School of Medicine at the University of Pennsylvania in Philadelphia, said the study involved 155,877 adults who participated in a randomized telephone survey. Respondents were asked about sleep disturbances and daytime tiredness. The study, published in the journal Sleep, found health problems and depression were associated with poor sleep, and women reported more sleep disturbances and tiredness than men. However, except for an uptick in sleep problems during middle age, more pronounced in women than in men, sleep quality improved consistently during a lifetime -- or at least that's how subjects perceived their sleep -- Grandner said. "Even if sleep among older Americans is actually worse than in younger adults, feelings about it still improve with age," Grandner said in a statement. "Once you factor out things like illness and depression, older people should be reporting better sleep. If they're not, they need to talk to their doctor. They shouldn't just ignore it."