Patterns and Correlates of Sedentary Behaviour Accumulation and Physical Activity in People with Chronic Obstructive Pulmonary Disease: A Cross-Sectional Study.

Few studies have used 24-hour accelerometery to characterise posture and movement patterns in people with chronic obstructive pulmonary disease (COPD). This study aimed to quantify sedentary behaviour (SB), patterns of SB accumulation and physical activity (PA) in people with COPD, and to examine physiological and functional capacity correlates of total SB and patterns of SB accumulation. SB and PA were assessed continuously over seven days using thigh-worn accelerometery in people with COPD. Participants were regarded as "sedentary" if combined sitting/reclining time accounted for ≥70% of waking wear time. Differences in patterns of SB accumulation and PA were compared between "sedentary" and "non-sedentary" participants. Physiological and functional capacity correlates of SB were explored using univariate analysis. Sixty-nine people with COPD (mean (SD) age 74 (9) years, FEV1 55% (19) predicted) had sufficient wear data for analysis. Mean sedentary time was 643 (105) minutes/day (71% (11) of waking wear time), of which 374 (142) minutes/day were accumulated in prolonged bouts of ≥30 min. "Sedentary" participants had a more unfavourable pattern of SB accumulation and spent less time in PA of any intensity. Sedentary time, expressed as a proportion of waking wear time, was inversely correlated with light (r = -0.97, p < .01) and moderate-to-vigorous intensity PA (r = -0.55, p < .01) and exercise capacity (r = -0.33, p < .01), but not with age, body mass index or lung function. People with COPD had high total SB and accumulated the majority of SB in prolonged bouts. High total SB was correlated with low physical activity and exercise tolerance.