You may wonder just how much exercise you need to reap these and other rewards—after all, your time is limited. At a minimum you probably need 30 minutes a day with increasing benefits found at 300 minutes a week. Another way to look at it is the number of steps taken in a day. For weight loss, building up to 10,000 steps a day is probably enough. To maintain weight loss, you may need an average of 15,000 steps.