Physical inactivity in patients with COPD, a controlled multi-center pilot-study

Abstract

Background: Physical activity (PA) has been reported to be reduced in severe chronic obstructive pulmonary disease (COPD). Studies in moderate COPD are currently scarce. The aim of the present study was to investigate physical activity in daily life in patients with COPD (n=70) and controls (n=30).

Methods: A multi-center controlled study was conducted. PA was assessed using a multisensor armband device (SenseWear, BodyMedia, Pittsburgh, PA) and is reported as the average number of steps per day, and the time spent in mild and moderate physical activity.

Results: Patients suffered from mild (n=9), moderate (n=28), severe (n=23) and very severe (n=10) COPD. The time spent in activities with mild (80 + or - 69 min vs 160 + or - 89 min, p<0.0001) and moderate intensity (24 + or - 29 min vs 65 + or - 70 min; p<0.0036) was reduced in patients compared to controls. The number of steps reached 87 + or - 34%, 71 + or - 32%, 49 + or - 34% and 29 + or - 20% of control values in GOLD-stages I to IV respectively. The time spent in activities at moderate intensity was 53 + or - 47%, 41 + or - 45%, 31 + or - 47% and 22 + or - 34% of the values obtained in controls respectively with increasing GOLD-stage. These differences reached statistical significance as of GOLD stage II (p<0.05). No differences were observed among centers.

Conclusions: Physical activity is reduced early in the disease progression (as of GOLD-stage II). Reductions in physical activities at moderate intensity seem to precede the reduction in the amount of physical activities at lower intensity.

Figure 1

The number of steps (upper panel) and the time spent in moderate physical activities (lower) in control subjects and patients with mild (GOLD I) to very severe (GOLD IV) COPD. Statistical significance of the ANOVA linear trend is indicated with *, post-hoc analysis indicated that physical activity was significantly different from controls as of GOLD-stage II.

Figure 2

Relation between the numbers of steps per day and the time spent in mild activities (Left panel) and the time spent in moderate intensity (Right panel) in patients (open symbols) and control subjects (closed symbols).