Table 3.

Relationship between clinical variables and the physical activity level (n=18)

Variables	PAEE		Sedentary		Moderate		Moderate/sedentarya
	r	p-value	r	p-value	r	p-value	r	p-value
Age, years	−0.51	0.031	−0.09	0.73	−0.37	0.13	−0.40	0.10
BMI, kg/m2	0.23	0.37	0.38	0.12	−0.24	0.34	−0.23	0.36
FVC, % predicted	−0.08	0.75	−0.53	0.02	0.13	0.60	0.20	0.44
FEV1, % predicted	−0.17	0.49	−0.55	0.02	−0.06	0.82	−0.04	0.89
PaO2, Torr	−0.37	0.21	−0.29	0.34	−0.46	0.11	−0.39	0.19
6MWD, m	−0.03	0.91	−0.30	0.25	0.22	0.39	0.36	0.16
ESMCSA, mm2	0.72	<0.001	0.02	0.92	0.19	0.45	0.32	0.20

Notes: r is the correlation coefficient; PaO₂ is the arterial oxygen tension at rest under room air condition. Data are expressed by Pearson’s correlation coefficient except FVC % predicted. Spearman’s rank correlation coefficient was used in case of FVC % predicted.

^aModerate/sedentary was calculated as the ratio of the moderate physical activity time to sedentary time.

Abbreviations: PAEE, physical activity-related energy expenditure; 6MWD, 6-minute walk distance; ESMCSA, cross-sectional area of erector spinae muscles; FVC, forced vital capacity; FEV₁, forced expiratory volume in 1 second; BMI, body mass index.