From ABC News:
The old benchmark of 150 minutes per week of moderate activity (or 75 minutes of vigorous activity) originated in 1995. The “rules”: Each time you exercise, it should be for at least 10 minutes.
“For about 30 years, guidelines have suggested that moderate-to-vigorous activity could provide health benefits, but only if you sustained the activity for 10 minutes or more,” an author of the research, William E. Kraus, M.D., of the Duke University School of Medicine, said in a press release. “That flies in the face of public health recommendations, like taking the stairs instead of the elevator, and parking farther from your destination. Those don’t take 10 minutes, so why were they recommended?
“The new study finds that the length of each bout or episode of exercise is unrelated to the benefit seen in living longer. Five minutes of jogging, researchers said, “counts” toward better health.