Physical Activity Patterns in Patients in Different Stages of Chronic Obstructive Pulmonary Disease

Figures & data

Table 1  Test subject characteristics

	Healthy subjects (n = 17)	Mild COPD (n = 11)	Moderate COPD (n = 21)	Severe COPD (n = 12)	p-value
Age (years)	58.4 ± 4.8	63.5 ± 5.8	63.9 ± 7.6	62.7 ± 7.6	ns
Height (cm)	172.4 ± 7.7	167.6 ± 3.2	168.8 ± 8.3	170.0 ± 9.5	ns
Weight (kg)	75.3 ± 9.5	73.1 ± 16.4	80.4 ± 21.7	76.7 ± 17.1	ns
BMI (kg/cm^2)	25.2 ± 1.8	25.9 ± 5.3	28.0 ± 6.3	26.3 ± 4.2	ns
VC (l)	3.9 ± 0.8	3.5 ± 0.5	3.0 ± 0.8*	2.7 ± 0.8*	<0.001
FEV1,0 (l/s)	3.0 ± 0.6	2.3 ± 0.4*	1.7 ± 0.3*	1.2 ± 0.3*	<0.001

All values are expressed as mean ± sd.

*Significantly lower compared with healthy subjects.

Abbreviations: COPD, chronic obstructive pulmonary disease; ns, not significant; BMI, body mass index; VC, vital capacity; FEV_1,0, forced expiratory volume in 1 sec.

Table 2  Exercise capacity expressed as distance walked in 6 min, fat free mass and physical activity variables in the different study groups

	Healthy subjects	Mild COPD	Moderate COPD	Severe COPD
	(n = 17)	(n = 11)	(n = 21)	(n = 12)	p-value
Distance walked in 6 min (m)	616 ± 60	485 ± 75*	439 ± 66*	404 ± 96*	<0.001
Fat free mass (%)	36 ± 6	37 ± 6	37 ± 7	37 ± 6	ns
MVPA (min)† (range)	24.6 (10.1–105.4)	13.2 (0.9–75.3)	7.5 * (0.1–73.7)	7.0 * (0.3–82.6)	0.002
Mean physical activity (counts/min)	365 ± 134	294 ± 136	229 ± 123*	215 ± 144*	0.01
Time spent sedentary (min)	523 ± 67	433 ± 73	478 ± 93	483 ± 89	Ns

Values are expressed as mean ± sd if not otherwise indicated.

†Values are expressed as median and range, ANOVA performed on natural logarithm (ln) MVPA.

*Significantly lower compared with healthy subjects.

Abbreviations: COPD, chronic obstructive pulmonary disease; ns, not significant; MVPA, time spent moderately or vigorously active.

Table 3  Standardized regression coefficients (β), explanatory power (R² adjusted) and p-value when examining the associations between exercise capacity and of percent of predicted FEV_1,0, MVPA, mean physical activity level and time spent sedentary in the patients.

Association between exercise capacity and	β	R^2 adjusted	p-value
FEV1,0	0.363	0.110	0.02*
MVPA	0.335	0.090	0.03*
MVPA after controlling for FEV1,0 and gender	0.381	0.298	0.01*
Mean physical activity	0.336	0.091	0.03*
Mean physical activity after controlling for FEV1,0 and gender	0.333	0.261	0.02*
Time spent sedentary	-0.094	-0.015	0.55
Time spent sedentary after controlling for FEV1,0 and gender	-0.155	0.176	0.32

*Significant association (p ≤ 0.05).

Abbreviations: FEV_1,0, forced expiratory volume in one second; MVPA, time spent moderately or vigorously active.