Table 4– Relationship of 6-min walking distance to physical activity in adults with chronic respiratory disease
First author [ref.]DiagnosisSubjects nPhysical activity measurePearson’s rSpearman’s rho
Pitta [72]COPD50Walking time in daily life0.75
Garcia-Rio [73]COPD110Vector magnitude units on accelerometry0.72
Hernandes [74]COPD40Walking time in daily life0.42
Intensity of movement0.64
Hill [75]COPD26Daily energy expenditure0.40
Borges [76]COPD20Walking time in hospital0.57
20Walking time in daily life 1 month after hospital discharge0.71
Troosters [77]CF64Time spent in vigorous physical activity0.45
Mainguy [78]PAH-SSc10Number of daily steps0.85
PAH15Number of daily steps0.76
PAH15Energy expenditure0.52
PAH15Time spent in moderate physical activity0.52
Pugh [79]PAH20Total activity counts0.72
Langer [80]LTC, COPD and ILD96Number of daily steps0.65
Minutes of activity ≥2 METS0.58
Wickerson [81]LTC, ILD24Number of daily steps0.59
Time spent in moderate to vigorous physical activity0.56
Dale [42]ARPD25Number of daily steps0.38
  • COPD: chronic obstructive pulmonary disease; CF: cystic fibrosis; PAH: pulmonary arterial hypertension; SSc: systemic sclerosis; LTC: lung transplant candidates; ILD: interstitial lung disease; ARPD: asbestos-related pleural disease; METS: metabolic equivalents.