Pedometers are devices that are worn on the body or clipped onto a piece of clothing. They calculate the number of steps you've taken in a certain period of time. Many pedometers also calculate heart rate and calories burned. Pedometers can be an effective tool for motivating you to exercise. Whether you're a runner or walker, pedometers can help you reach your fitness goals. Follow the links below to find WebMD's comprehensive coverage about how pedometers work, the benefits of using one, and much more.