Physical activity in daily life in patients with idiopathic pulmonary fibrosis.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is characterized by progressive impairment of lung function and degradation of daily activity; however, this degradation has not been adequately elucidated. The objective of this study was to measure the physical activity of patients with IPF to determine its relationships with physiological parameters and survival rate.

METHODS: In total, 31 patients with IPF and 20 age-matched healthy participants were enrolled in this study. Physical activity was assessed using a physical activity monitor. The relationships among physical activity, physiological data, questionnaire-based patient-centered data, and survival were examined.

RESULTS: Physical activity, expressed as daily activity energy expenditure (AEE), was significantly lower, and the percentage of sedentary time was significantly longer in patients with IPF than in healthy participants. Moreover, AEE was moderately correlated with body-mass index, forced vital capacity, diffusing capacity of carbon monoxide, and partial arterial pressure of oxygen. Relatively strong correlation was also observed between AEE and the 6-min walk distance, but not with daily dyspnea, depression, and health-related quality of life scores. Prognostic analysis indicated that daily AEE was a significant predictor of survival.

CONCLUSIONS: Patients with IPF were significantly inactive compared with age-matched healthy participants. In patients with more impaired physiological functions, the lower the physical activity was, the more was the sedentary time increased. Furthermore, lower daily physical activity resulted in significantly worse survival.