Bicycling is great exercise. In fact, riding your bike for an hour at a steady pace can burn up to 533 calories for a 140-pound individual. However, it's important to keep safety precautions in mind when you go for a ride. Most people don't even consider wearing a helmet when they go for a leisurely bike ride. But it can prevent serious injuries. According to the BHSI, 540,000 bicyclists visit the ER with injuries every year. One in eight of these people suffers a brain injury. Ironically, between 45 to 88 percent of these injuries can be prevented with a helmet. Cyclists not wearing helmets are 14 times more likely to be involved in a fatal crash than their helmet-wearing counterparts. And if you think helmets are child's play, that's not the case. The average age of the bicyclist killed on the highway is 40.