Movement, non-movement behaviors and physical performance in older adults: An isotemporal substitution approach.

Introduction: The time dedicated to movement (e.g., physical activity) and non-movement behaviours (e.g., sitting) has important implications in terms of maintaining physical performance (PP), while it has also been independently associated with better or poorer PP. Physical performance in older adults may be significantly improved by changing daily movement and non-movement behaviours. Therefore, the aims of this study were: (i) to analyse the associations of the time dedicated to movement and non-movement behaviours (i.e., lying down, sitting, standing, and locomotion) with PP (Time up and Go test and the Short Physical Performance Battery); and (ii) to examine how theoretically reallocating time between these behaviours is associated with this outcome.

Methods: Forty-nine older adults (mean age: 82.9 ± 6.9 yrs) wore an activity monitor to measure periods of lying down, sitting, standing and locomotion. PP measures included the Time up and Go test (TUG) and the Short Physical Performance Battery (SPPB).

Results: Replacing 60 min∙d-1 of lying down time with standing resulted in a significant improvement in TUG (β = -4.99, 95% CI = -8.81, -1.17), and SPPB (β = -0.93, 95% CI = 0.04, 1.82). Likewise, replacing 60 min∙d-1 of sitting time with standing also resulted in a significant improvement in TUG (β = -4.51, 95% CI = -8.67, -0.37). Meanwhile, replacing 60 min∙d-1 of lying down or sitting time with locomotion resulted in a significant improvement in the Sit to Stand test of the SPPB (β = 0.82, 95% CI = 0.14, 1.49, and β = 0.90, 95% CI = 0.23, 1.56, respectively).

Discussion And Conclusion: Isotemporal substitution modelling suggests that replacing 60 min∙d-1 of non-movement or stationary behaviours, such as standing, with an equivalent locomotion time may contribute to improved PP in older adults.