It is difficult to compare the observed results with those of other studies because of differences in measures of PA. For people with COPD the time spent in LPA may be com¬parable with walking time because they tend to walk slowly. The number of steps/day is commonly used as a measure of PA, and 1,000 steps/day is estimated to be equivalent to 10 minutes of brisk walking.4,38 Neither of these methods provides a measure of the intensity of PA, but they do enable crude comparisons across studies. In addition, it is important to note that PA measures in this study reflect free-living PA and do not include the activity associated with the exercise sessions.