The independent associations of physical activity and sleep with neural activity during an inhibitory task: cross-sectional results from the MONITOR-OA study.

Sleep and physical activity (PA) are important for the maintenance of executive functions. Whether these lifestyle factors independently contribute to associated neural correlates of executive functions is unknown. We therefore investigated the independent associations of PA and sleep with neural activity during executive performance using task-based functional magnetic resonance imaging (fMRI). Baseline data from a subset of participants (n = 29) enrolled in a randomised trial were used for this cross-sectional analysis. We measured PA, sleep duration and efficiency for 7 days using the SenseWear Mini and examined neural activity underlying response inhibition using the Go/NoGo executive performance task. Brain activation patterns during the NoGo condition were contrasted to activation patterns during the Go condition (i.e., NoGo-Go). We constructed two separate models (controlling for age, sex, and education) to examine the independent associations of (i) PA and sleep duration; and (ii) PA and sleep efficiency with brain activation. Significant clusters were corrected for multiple comparisons (p < 0.05) to determine region-specific activation patterns. The mean (SD) participant age was 61 (9) years, and 79% were female. PA was independently associated with greater task-related blood-oxygen-level dependent (BOLD) signal activity in the left cingulate gyrus; longer sleep duration was independently associated with greater BOLD signal activity in the left putamen. Higher sleep efficiency was independently associated with increased BOLD signal activity in the left hippocampus. PA, sleep duration, and efficiency are each independently associated with greater neural activity underlying response inhibition, which further illustrates that PA and sleep are each uniquely important for brain health.

Cross-sectional and longitudinal neural predictors of physical activity and sedentary behaviour from a 6-month randomized controlled trial.

A sedentary lifestyle offers immediate gratification, but at the expense of long-term health. It is thus critical to understand how the brain evaluates immediate rewards and long-term health effects in the context of deciding whether to engage in moderate-to-vigorous physical activity (MVPA) or sedentary behaviour (SB). In this secondary analysis of a 6-month randomized controlled trial to increase MVPA and reduce SB among community-dwelling adults, we explored how neural activity during an executive control task was associated with MVPA and SB levels. At baseline, a subset of participants (n = 26/61) underwent task-based functional magnetic resonance imaging (fMRI) to examine neural activity underlying executive control using the Now/Later task. MVPA and SB were measured objectively using the Sensewear Mini at baseline, and 2, 4, and 6 months follow-up. We then examined the associations of baseline neural activation underlying executive control with: (1) baseline MVPA or SB; and (2) changes in MVPA and SB over 6 months. Our results determined that there is a complex neurocognitive system associated with MVPA levels, while SB appears to lack any neurocognitive control. In other words, MVPA appears to require neurocognitive effort, while SB may be the default behavioural pattern in adults.

Effects of Resistance Exercise with Instability on Cognitive Function (REI Study): A Proof-Of-Concept Randomized Controlled Trial in Older Adults with Cognitive Complaints.

BACKGROUND: Activities which simultaneously challenge both physical and cognitive function are promising strategies for promoting cognitive function. OBJECTIVE: To examine the effects of resistance exercise with instability and traditional resistance exercise compared with a health education control on cognitive function in older adults with cognitive complaints. METHODS: Sixty-seven participants were randomized to either 12 weeks of thrice-weekly resistance exercise (RE = 23), RE with instability (REI = 22), or a weekly health education control (CON = 22). At each training session, RE and REI participants performed seven exercises for three sets and 10-15 repetitions. REI participants performed each exercise using instability devices. The primary outcome was a composite score of global cognitive function. Secondary outcomes included composite scores for cognitive sub-domains and physical function. RESULTS: Most participants were women (REI: 77%; RE = 78%; CON = 77%; mean age of 71 years), and did not need transport to the intervention site. At completion, compared with CON, REI and RE did not significantly improve on global cognition or each cognitive sub-domain. Both exercise groups improved on the timed up and go (REI - CON: -1.6 s, 95% CI: [-2.6, -0.5]; RE - CON: -1.4 s, 95% CI: [-2.4, -0.5) and 1-RM (REI - CON: 24 kg, 95% CI: [11, 36]; RE - CON: 25 kg, 95% CI: [12, 37]). An exploratory contrast showed that compared with RE, REI promote greater gains on global cognition (2.20, 95% CI: [0.10, 4.31]) and memory (1.34; 95% CI: [0.15, 2.54]). CONCLUSION: REI did not substantially improve cognitive function but did promote physical function among older adults with cognitive complaints. However, compared with RE, REI improved global cognition and memory.