Walking is a great way to improve or maintain your overall health. Just 30 minutes every day can increase cardiovascular fitness, strengthen bones, reduce excess body fat, and boost muscle power and endurance. Physical activity does not have to be vigorous or done for long periods in order to improve your health. At a brisk walking pace, you would burn 100 to 300 calories in 30 minutes (depending on your weight) or 200 to 600 calories in an hour. By walking for 30 minutes or more at a time, some of those calories will be from stored fat. During the first 30 minutes of exercise, your body is burning sugars stored as fuel.