Stand up to Dementia: The Association between Sedentary Behaviour and Cognitive Functioning in Older Adults

The inactivity physiology paradigm (Hamilton, Healy, Dunstan, Zderic, & Owen, 2008) proposes that excessive sedentary behaviour has adverse health consequences independently from the effects of insufficient exercise. Whilst the association between exercise and cognitive functioning in older adults is relatively well established, independent effects of sedentary behaviour require further research. The current study aimed to explore the association between cognitive functioning and sedentary behaviour in older adults, as well as associations with a number of specific sedentary activities. A cross-sectional study was conducted involving 27 adults aged 68 to 90. Sedentary behaviours were both subjectively and objectively measured through self-reports and activPAL activity monitoring devices. Self-reported time in a number of specific activities including television viewing, computer use, socialising, reading and hobbies was also collected. Cognitive functioning was assessed using Cogstate computer-based tests and the Mini Mental State Examination. It was hypothesised that overall sedentary time would be associated with poorer cognitive functioning. However, results showed that more prolonged bouts of sedentary behaviour, rather than overall sedentary time, were associated with decreased working memory, verbal learning and global cognitive functioning. The relationship remained significant between working memory and number of sedentary bouts greater than 30 minutes even after controlling for age and physical activity. A trend between overall sedentary time and poorer memory was also revealed, which should be further explored in research with greater statistical power. To our knowledge, the current study is the first to show an association between prolonged bouts of sedentary behaviour and cognitive functioning in older adults. Whilst further research is required with larger sample sizes, this novel finding extends current literature on cognitive functioning within the inactivity physiology paradigm