If you're new to exercise, start slow and easy. At first, walk only as far or as fast as you find comfortable. If you can walk for only a few minutes, let that be your starting point. For example, you might try short daily sessions of five to 10 minutes and slowly build up to 15 minutes twice a week. Then, over several weeks, you can gradually work your way up to 30 to 60 minutes of walking most days of the week.