Walking is the easiest and simplest form of exercise. By putting one foot in front of the other, you can start to walk your ways towards a healthier lifestyle. Walking is an easy way to challenge the cardiovascular system (心血管系统), while at the same time building muscles. But to achieve these goals, a little more than a gentle walk around the block is required. Walking actually burns as many calories (卡路里) as running the same distance—if done in the correct manner and at a reasonable pace (步伐). Start with a basic program that you can complete three or four times a week. This should include five main steps: —A beginning warm-up for about 5 minutes. —A little bit faster period of 5 minutes at medium level (中等速度). —A 10-minute "burning" at a high level. —A 5-minute slow down period at a medium level. —A 5-minute cool down period at a low level again. A suitable walking pace of around 5 kilometers per hour will burn around 80 calories in 30 minutes. Compared with running the same distance, walking in the recommended way bums ______.
A. fewer calories B. more calories C. a fixed number of calories D. the same number of calories