Purpose: Little is known about physical activity in individuals with interstitial lung disease (ILD). The objectives of this study were (1) to objectively measure physical activity in lung transplant candidates with ILD, (2) to compare levels of physical activity on rehabilitation and nonrehabilitation days, and (3) to explore the relationships between physical activity and functional measures.
Methods: Twenty-four (14 men) lung transplant candidates with ILD on long-term oxygen therapy, who were enrolled in an exercise-based rehabilitation program, underwent measurements of physical activity using accelerometry (daily steps and time spent in moderate-intensity physical activity per day), functional exercise capacity (6-minute walk distance), and muscle strength (isometric quadriceps torque).
Results: Lung transplant candidates with ILD had reduced levels of physical activity compared to the general population but were more active on rehabilitation versus nonrehabilitation days (M ± SD) (daily steps, 3780 ± 2196 vs 2138 ± 1353; P < .001; and time spent in moderate-intensity activity per day, 4.5 [interquartile range, 1.5-17] minutes vs 2 [interquartile range, 1-3.5] minutes). The 6-minute walk distance showed the strongest correlation to daily steps (r = 0.59, P < .01) and time spent in moderate-intensity physical activity per day (r = 0.56, P < .01).
Conclusions: Individuals with advanced ILD are markedly inactive; however, physical activity levels were significantly higher on rehabilitation days. The importance of physical activity as a rehabilitation outcome in ILD warrants further investigation.