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Walking -- like swimming,bicycling and running -- is an aerobic exercise which builds the capacity for energy output and physical endurance by increasing the supply of oxygen to skin and muscles.Such exercise may be a primary factor in the prevention of heart and circulatory disease.
As probably the least strenuous,safest aerobic activity,walking is the most acceptable exercise for the greatest number of people.Walking at comfortable speed improves the efficiency of the cardio-respiratory system by stimulating the lungs and heart,but at a more gradual rate than most other forms of exercise.