Accelerometer-assessed light physical activity is protective of future cognitive ability: A longitudinal study among community dwelling older adults

Objective
Physical activity (PA), especially moderate-to-vigorous intensity, could protect older adults from cognitive impairment. However, most literature is based on self-reported PA which is limited by recall bias. Light PA is popular among older adults, but a paucity of objective longitudinal data has considered the relationship between light PA and cognitive ability. We examined if a higher level of objectively measured light PA, independent of moderate-to-vigorous physical activity (MVPA), was prospectively associated with better cognitive ability in older adults.
Methods
A longitudinal study over 22.12 (± 1.46) months including 274 community-dwelling older adults across 14 regions in Taiwan was undertaken. Cognitive ability was obtained using a Chinese version of the Ascertain Dementia 8-item Questionnaire (AD8) and light PA and MVPA captured by 7 days accelerometer positioned on waist. Multivariable negative binomial regression adjusted for confounders were undertaken.
Results
274 participants (74.52 years, 45.6% male) attended the follow-up (96.1%). Higher light PA, independent from MVPA, was associated with a reduced rate of decline in cognitive ability (rate ratio 0.75 [0.60–0.92]). MVPA, was also associated with a reduced decline in cognitive ability (rate ratio 0.85 [0.75–0.95]). Light PA was protective of cognitive ability in sensitivity analyses removing participants with activities of daily living difficulties, depressive symptoms and cognitive impairment at baseline.
Conclusion
Our data suggest that light PA may offer a protective influence of future cognitive ability in community dwelling older adults. The promotion of light PA may be a valuable means to maintain cognitive ability in older age.