Physical Activity Behaviors Are Similar Among Preserved Ratio Impaired Spirometry (PRISm), Normal Spirometry And Moderate COPD

Recommended physical activity (PA) to prevent or manage chronic diseases is >150 min/week moderate-to-vigorous PA (MVPA) or > 75 min/week vigorous PA (VPA). In the elderly, completing MVPA >300 min/week is associated with further mortality risk reduction. Smokers with preserved ratio impaired spirometry (PRISm) have lower 6-minute walk distance (6MWD) and worse symptoms compared to normal spirometry smokers (CON). How this associates with PA behaviors is unknown. PURPOSE: To compare PA behaviors among PRISm, CON and moderate chronic obstructive pulmonary disease (COPD). METHODS: 21 PRISm, 76 CON and 40 moderate COPD completed the Muscle Health Study, an ancillary of COPDGene. Daily PA by triaxial accelerometry was used to determine duration of MVPA (>3 METs) and VPA (>6 METs) over 7 days, where ≥4 days and ≥ 8 h/day (8 AM-11 PM) was required for inclusion. Participants were characterized by anthropometrics, spirometry, 6MWD, symptoms (mMRC, CAT), muscle oxidative capacity assessed from the calf muscle V̇O2 recovery rate constant (k) using near-infrared spectroscopy, among others. One-way ANOVA with Dunnett post hoc, Kruskal Wallis H test or Chi-square test assessed differences among groups, with PRISm as reference group. RESULTS: 121(88%) participants met PA measurement inclusion criteria. A majority of participants (76-88%) completed >150 min/week MVPA, 65-85% completed >300 min/week MVPA, but only 13-37% completed >75 min/week VPA. Time in MPA, MVPA, or VPA was not different among groups (p ≥ 0.12; Table), despite impaired pulmonary function, shorter 6MWD, and greater incidence of symptoms and comorbidities in PRISm (Table). Muscle oxidative capacity was lower than CON in moderate COPD, but not in PRISm (Table). CONCLUSIONS: Engagement in MVPA was not impaired in PRISm patients, despite impaired pulmonary function, exercise performance and worse symptoms. Our findings also oppose the notion that low PA causes impaired muscle oxidative function in COPD.NIH R01HL151452