Pulmonary rehabilitation clearly increases exercise capacity, but its effect on physical activity in the home and community settings is less clear. It may take a longer time for this increase in physical activity to occur. It has been stated in an editorial that it takes 3 months to train the muscles but 6 months to train the brain. The Investigators will first evaluate the change in physical activity following pulmonary rehabilitation using state-of-the-science motion detectors, then Investigators will follow the trajectory of physical activity over the next several months.