Research
Physical exercise attenuates cognitive decline and reduces behavioural problems in people with mild cognitive impairment and dementia: a systematic review

https://doi.org/10.1016/j.jphys.2019.11.014Get rights and content
Under a Creative Commons license
open access

Abstract

Questions

What is the effect of physical exercise on cognitive decline and behavioural problems in people with mild cognitive impairment (MCI) or dementia? What is the effect of physical exercise on particular domains of cognitive function? How do training protocols and patients' characteristics influence the outcomes?

Design

Systematic review and meta-analysis of randomised trials.

Participants

People with MCI or dementia as their primary diagnosis.

Intervention

Physical exercise.

Outcome measures

Cognitive function including global cognition, memory, executive function, reasoning, attention, language, and behavioural problems.

Results

Forty-six trials involving 5099 participants were included in this review. Meta-analysis of the data estimated that aerobic exercise reduced the decline in global cognition, with a standardised mean difference (SMD) of 0.44, 95% CI 0.27 to 0.61, I2 = 69%. For individual cognitive functions, meta-analysis estimated that exercise lessened working memory decline (SMD 0.28, 95% CI 0.04 to 0.52, I2 = 40%). The estimated mean effect on reducing the decline in language function was favourable (SMD 0.17), but this estimate had substantial uncertainty (95% CI –0.03 to 0.36, I2 = 67%). The effects of exercise on other cognitive functions were unclear. Exercise also reduced behavioural problems (SMD 0.36, 95% CI 0.07 to 0.64, I2 = 81%).

Conclusion

Physical exercise can reduce global cognitive decline and lessen behavioural problems in people with MCI or dementia. Its benefits on cognitive function can be primarily attributed to its effects on working memory. Aerobic exercise at moderate intensity or above and a total training duration of > 24 hours can lead to a more pronounced effect on global cognition.

Key words

Exercise
Dementia
Cognitive dysfunction
Systematic review
Meta-analysis

Cited by (0)

Footnotes: a Comprehensive Meta-analysis Version 2, Biostat, Englewood, NJ, 2005.

b Review Manager Version 5.3, Copenhagen: The Nordic Cochrane Centre, The Cochrane Collaboration, 2014.

eAddenda: Figures 3, 5, 7, 9, 11, 13, 15, 17 and Appendices 1, 2, 3 can be found online at https://doi.org/10.1016/j.jphys.2019.11.014.

Ethics approval: Nil.

Competing interests: Nil.

Source(s) of support: This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.