1. Physical activity helps you lose weight by burning calories, boosting resting metabolism, and buffering you from bone and muscle loss that can result if you diet alone.
2. High levels of physical activity can decrease your risk of colon cancer by 40 to 50 percent.
3. Exercise helps you get better sleep. In one study, people who walked more than six blocks a day had 1/3 fewer insomnia problems than their less active cohorts.
4. Walking 30 minutes five days a week can increase your life span by one and a half years. Running can add up to four years according to a 2005 study published in the Archives of Internal Medicine. It's never too late to increase longevity.