Objectively measured physical activity is related to cognitive function in older adults

Objectives: To explore the relationship between cognitive functioning and time spent at different intensities of physical activity (PA) in free-living older adults.

Design: Cross sectional analyses.

Setting: Continuing care retirement communities.

Participants: Older adults residing in seven continuing care retirement communities in San Diego County with an average age of 83; 70% were female, and 35% had a graduate-level education (N = 217).

Measurements: PA was measured objectively using hip worn accelerometers with data aggregated to the minute level. Three cut points were used to assess low light-intensity PA (LLPA), high light-intensity PA (HLPA), and moderate- to vigorous-intensity PA (MVPA). The Trail Making Test (TMT) Parts A and B were completed, and time for each test (seconds) and time for Part B minus time for Part A (seconds) were used as measures of cognitive function. Variables were log-transformed and entered into linear regression models adjusting for demographic factors (age, education, sex) and other PA intensity variables.

Results: LLPA was not related to any TMT test score. HLPA was significantly related to TMT A, B, and B minus A but only in unadjusted models. MVPA was related to TMT B and B minus A after adjusting for demographic variables.

Conclusion: There may be a dose response between PA intensity and cognitive functioning in older adults. The stronger findings supporting a relationship between MVPA and cognitive functioning are consistent with previous observational and intervention studies.