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.