Interaction between Physical Activity and Smoking on Lung, Muscle, and Bone in Mice.

Physical inactivity is an important contributor to skeletal muscle weakness, osteoporosis, and weight loss in chronic obstructive pulmonary disease. However, the effects of physical inactivity, in interaction with smoking, on lung, muscle, and bone are poorly understood. To address this issue, male mice were randomly assigned to an active (daily running), moderately inactive (space restriction), or extremely inactive group (space restriction followed by hindlimb suspension to mimic bed rest) during 24 weeks and simultaneously exposed to either cigarette smoke or room air.