Lying: torso and thigh sensors indicate horizontal, Standing: torso and thigh sensors indicate vertical, Sitting: torso sensor = vertical, thigh sensor = horizontal. Duplicate sensor sets are used in all subjects to gather duplicate data every ½ second for 14 days. The physical activity data are combined with the breath measurement data to allow us to measure all forms of activity. The following are key features; specialized sensors (accelerometers) are completely integrated with the inclinometers so that data on body position and movement are continuously gathered; the sensors are attached to the subject using a harnesses that allows a full range of daytime and nighttime physical activities as well as bathroom use.