 After your first study visit, you will be given an activity monitor and instructions to wear it on your waistband or belt like a pedometer, during the time you are awake, for 7 days in a row. The activity monitor will record your daily activity. At the end of the 7 days, you will be asked to return the activity monitor using a pre-addressed, postage-paid return envelope that you will be given to you with the monitor. 