"Bicycling is healthy: it increases physical activity, improves cardiovascular health, and reduces obesity and disease. Bicycling also can be an excellent mode of transportation for people of all ages. In fact, bicycling to school has been shown to improve cardiovascular fitness and overall health among children and adolescents. As with virtually any kind of sport or physical activity, bicycling poses some risk of injury, but recent studies show that the health benefits of bicycling far exceed the health risks. More over, as bicycling levels increase, injury rates fall, making bicycling safer and providing even larger net health benefits."
ALR_Brief_DailyBikeTravel_May2013