Longitudinal Patterns of Objectively Measured Physical Activity Among Older Adults in a Population-Based Study

Background: The steep decline in physical activity (PA) among the oldest old is not well understood. Longitudinal objective PA data can give insights about how amount and bouts of PA and sedentary behaviour (SB) change with age.

Methods: Men aged 70-90 years, from a UK population-based cohort wore GT3x accelerometer over the hip in 2010, 2011 and 2012 (66%, 68% and 68% response rates). Multilevel models were used to estimate change in activity. Men were grouped according to achieving ≥150 minutes/week of MVPA in bouts of ≥10 minutes at two or three time-points.

Results: 1419 ambulatory men had ≥600 minutes weartime on ≥3 days at ≥2 time-points. At baseline men took 4870 steps/day, and spent 72.3% of their day in SB, 23.3% in light PA and 4.4% in MVPA. Mean change per year was -380 steps, +1.1% SB, -0.67% light PA and -0.45% MVPA each day, (all p<0.001). 4 main trajectories of change over 3 years were identified; 76.3%(n=1083) never met guidelines “stable low”, 7.9%(n=112) always met guidelines “stable high”, 8.2%(n=116) were “decreasers”, and 4.9%(n=69) ”increasers”. “Decreasers”, spent 69.4% of each day in SB, which increased by 1.9%/year (p<0.005), light activity remained at 23.2% (change -0.19%/year, p=0.4), and total MVPA decreased from 7.1% by -1.8%/year, (p<0.001). Number of sedentary bouts ≥30 minutes increased from 4.8 by 0.15/year (p=0.02).

Conclusion: Among older adults, the steep decline in total PA appears to be driven by reductions in MVPA whilst light PA is relatively spared and sedentary time and long sedentary bouts increase.