Why do they run? Running. It’s painful, tedious, and exhausting. So, why do so many Americans do it? People run for many reasons. Most often, people run to stay in shape and to reach an ideal body weight. Studies show that a combination of diet and exercise is the most effective way to lose weight, as it triggers a loss of body fat and a proportional increase of lean tissue. Running, a rigorous cardiovascular exercise, allows a person to burn an average of 100 calories per each mile he or she runs. Other popular activities, such as biking and walking, only burn a fraction of those calories in the same amount of time. While the average human being burns about 2000-2500 calories a day by simply existing, running 5 miles a day can burn an additional 500 calories, making it a legitimate way to lose weight. Furthermore, running is an easily accessible activity with a decent pair of sneakers and some determination, anyone can run.