EXERCISE: CAN LESS BE MORE? The 20 Minute Workout. “Instead of asking how much exercise we need, some scientists are looking into how little we can do and still get maximal health and fitness benefits. The answer appears to be a lot less than most of us think — provided we’re willing to put in some effort. That’s the secret behind high-intensity interval training, or HIIT, an approach to training that compresses all of your exercise into only a few minutes.”