Sedentary Behaviour and Physical Inactivity in Patients with Chronic Obstructive Pulmonary Disease: Two Sides of the Same Coin?

Despite the growing interest in sedentarism, there is no available information on the profile of patients with COPD according to sedentary behaviour (SB) and with a detailed analysis of minute-by-minute bouts. Hence, the aims of this study were to quantify the time spent in SB, light activities and moderate-to-vigorous physical activities (MVPA) and to verify the relationship of MVPA and SB in individuals with COPD, as well as to identify the profile of those physically (in)active and (non)-sedentary. A cross-sectional study in which physical activity in daily life was objectively assessed through the use of SenseWear Pro 2 Armband (BodyMedia) during 2 consecutive week-days, 12h/day. Analysis was performed minute-by-minute for each day of each patient. MVPA comprised time spent >3 metabolic equivalents (MET), whereas light activities corresponded to time spent between 1.5 and 3 MET and SB to time spent <1.5 MET. A total of 137 subjects with COPD (66 +/- 8years; FEV1 46 [31-57] %pred; BMI 26 [22-30] kg/m(2)) were analysed. Time spent in MVPA and SB presented strong negative correlation (r = -0.72, P < 0.001). Minute-by-minute analysis showed that patients with COPD spend most of their time in SB. SB accounted for 40% of all bouts >1 minute, whereas only 14% these bouts concern MVPA. Patients combining two positive characteristics (physically active and non-sedentary) have better clinical profile than others. In conclusion, SB is negatively correlated with MVPA in patients with COPD. Furthermore, patients classified as physically active (i.e., those who reach MVPA recommendations) in combination with a non-sedentary lifestyle present markedly better clinical conditions.