Chillax. Your knees will be fine. That’s the message from University of North Carolina researchers to people who exercise up to two and a half hours a week. A university news release reports that the researchers, who analyzed data from more than 1,500 people age 45 and older, found that those who did moderate exercise–up to two and a half hours a week– did not increase their risk of developing knee osteoarthritis over a 6-year period. The study also found that people who did the most exercise- up to 5 hours a week – did have a slightly higher risk of knee osteoarthritis, but the difference was not statistically significant. Read more from the University of North Carolina.