Walking 30 minutes on a treadmill regularly can help a person obtain the 150 minutes a week of moderate intensity physical activity health experts recommend. This activity works the heart, lungs, and large muscle groups. It is a cardio workout that is accessible to people at all levels of fitness. The ADA recommends that new exercisers start by walking for roughly 15 minutes a few days a week and gradually build up to five 30-minute walking sessions per week. may also wish to start with a neutral incline to make their beginning exercise sessions easier.