We should get at least 30 minutes of moderate exercise 5 days a week. But is it OK to get all that exercise on weekends? Yes! The A.M.A. says we’ll get the same life-lengthening benefits because weekend warriors tend to push harder than weekDAY exercisers. So quality of exercise may be more crucial than quantity. Compared to sedentary people, weekend AND weekday exercisers are 40% less likely to die from heart disease. The only issue? Weekend-only workouts cause more injuries because they’re more intense. And strains and sprains are more likely after being sedentary all week.