Original researchLight physical activity is positively associated with cognitive performance in older community dwelling adults
Introduction
Participation in physical activity (PA) by older adults reduces the risk of chronic disease, and encourages the maintenance of muscle strength1 and functional independence.2 It is also possible that regular PA might delay the age-related decline in cognitive function.2
The collective evidence demonstrates PA positively influences cognition across a range of domains.3 A meta-analysis of prospective studies that examined the association between PA and cognitive decline in older adults found a low to moderate level of PA significantly (−35%) reduced the risk of decline.4 Others found an inverse relationship between increased muscle strength5 and cardiorespiratory fitness6 and cognitive decline.
Questionnaires and other self-report measures have historically been used to derive population-based measurements of habitual PA, despite their limited reliability and validity.7 Objective measures of PA are furthering our understanding of the association between cognition and PA, and there is emerging evidence cognitive function is improved by both light8 and moderate-to-vigorous PA.8, 9
Further population-based studies are required to clarify the association between cognition, muscle strength and objectively measured PA behaviours. In an ageing Australian population, understanding this association might aid the development of interventions aimed towards delaying or slowing the rate of cognitive decline. The aim of this study was to investigate cross-sectional associations between different intensities of PA, muscle strength and executive functioning as indexed by set-shifting and psychomotor performance in older adults. It was hypothesised that more active and stronger participants would have enhanced set-shifting and faster psychomotor speed whereas increased sedentary time would be associated with poorer set-shifting and psychomotor performance.
Section snippets
Method
Participants were drawn from the Tasmanian Older Adult Cohort (TASOAC), an ongoing, prospective, population-based study of community-dwelling older adults. An equal number of men and women between the ages of 50 and 79 years were randomly selected from the electoral roll in Southern Tasmania (population 229,000), with a response rate of 57%. Exclusion criteria included contraindication for magnetic resonance imaging and institutionalisation. Of the 1100 enrolled in the study, 1099 attended a
Results
Twenty outlier cases (9.5% of the sample, 10 Female) that had a standard score of 3 or greater were removed from the analyses. Another two cases (0.95% of the sample) were removed because of missing HVLT-R data, resulting in 188 participants being included in the analyses (see Table 1 for participant characteristics). The sample analysed differed little from the initial sample prior to exclusions (see Section 2). Examination of residuals scatter plots for TMT variables showed that the
Discussion
The utility of accelerometers to objectively measure PA behaviour distinguishes this study as one of the few that accurately quantifies the associations between cognitive functioning, muscle strength, and PA behaviour. In our cross-sectional analysis of older adults, older age and reduced cognitive functioning was negatively associated with psychomotor speed. However, there was no significant association between PA behaviour or muscle strength and psychomotor speed. Alternatively, when
Conclusion
This study found light PA is associated with higher levels of cognitive functioning in a sample of older adults. The significance of this finding should not be underestimated, as this is one of the few studies of its type to employ an objective measure of PA behaviours. Notwithstanding the existing evidence of the benefits of PA for cognitive functioning, our findings have important implications for the appropriate prescription of exercise to preserve older adult's executive functioning. For
Practical implications
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Higher levels of light PA may help older adults to preserve their executive functioning.
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A greater intensity of PA and increased sedentary time may not necessarily enhance cognitive functioning.
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Elderly individuals who are deconditioned or new to exercise might benefit physically and cognitively from light PA.
Acknowledgements
The TASOAC study was supported by the National Health and Medical Research Council of Australia; Arthritis Foundation of Australia; Tasmanian Community Fund; University of Tasmania Institutional Research Grants Scheme. This analysis was supported by the Australian Government's Collaborative Research Networks program. We wish to thank the TASOAC staff and volunteers, in particular the study coordinator Catrina Boon, and we are appreciative of the time and efforts of all the TASOAC participants.
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