Lazy Sundays: Role of day of the week and reactivity on objectively measured physical activity in older people

Abstract

Background: The aim of this study was to assess the effect of day of the week and wearing a device (reactivity) on objectively measured physical activity (PA) in older people. Methods: Walking duration as a measure for PA was recorded from 1333 German community-dwelling older people (≥65 years, 43.8% women) over 5 days using accelerometers (activPAL). Least-square means of PA with 95%-confidence intervals (95%-CI) from multi-level analysis were calculated for each day of the week and each measurement day (days after sensor attachment). Results: Walking duration on Sundays was significantly lower compared to working days (Sunday vs. Monday-Friday:-12.8 min (95%-CI:-14.7;-10.9)). No statistically significant difference compared to working days was present for Saturdays. The linear slope for measurement day and walking duration was marginal and not statistically significant. Conclusions: Studies using PA sensors in older people should assess Sundays and working days to adequately determine the activity level of the participants.