Evidence Summary (updated 2022)
The strongest evidence for promotion of physical activity in the context of dementia relates to disease prevention(1–3). Overall physical activity is more effective at reducing cognitive decline if part of a multidomain intervention(1,4,5).
The Lancet Commission for Dementia Prevention, Intervention Care 2017, led by Professor Gill Livingstone, recommend: “Active treatment of hypertension in middle aged (45–65 years) and older people (aged older than 65 years) without dementia to reduce dementia incidence. Interventions for other risk factors including more childhood education, exercise, maintaining social engagement, reducing smoking, and management of hearing loss, depression, diabetes, and obesity might have the potential to delay or prevent a third of dementia cases.”(1)
The benefits of physical activity for prevention may be improved if combined with broader strategies to promote a healthy lifestyle and managing cardiovascular risk factors including smoking cessation, managing high blood pressure, maintaining a healthy diet, maintaining a healthy weight and BMI, maintain alcohol consumption below 14 units per week/8 drinks, managing high cholesterol, maintain healthy blood sugars.
Maintaining recommended levels of physical activity may be associated with a 3 to 6% reduction in risk of dementia. Combined with maintaining ideal cardiovascular health across all modifiable risk factor risk reduction may be between 20 and 40%, with greatest risk reduction associated with risk of vascular dementia.
Longitudinal population studies demonstrate that older adults who exercise are more likely to maintain cognition than those who are physically inactivity. However, there is no randomised control trials that show exercise prevents cognitive decline. The evidence for the preventive benefits of physical activity may also be stronger in the context of maintaining an ideal cardiovascular health profile.
One meta-analysis by Sofi et al reported on 15 prospective cohort studies following up 33 816 individuals without dementia for 1–12 years and identified that physical activity had a significant protective effect against cognitive decline, with high levels of exercise being the most protective (hazard ratio [HR] 0·62, 95% CI 0·54–0·70).(2)
Another meta-analysis by Hamer et al; reported on follow-up of 163 797 participants without dementia, from 16 different studies, and found that the RR of dementia in the highest physical activity groups compared with the lowest was 0·72 (95% CI 0·60–0·86) and the RR of Alzheimer’s disease was 0·55 (95% CI 0·36–0·84).(3)
Brasure et al published a systematic review of 32 eligible trials, 16 with low to moderate risk of bias compared a physical activity intervention with an inactive control. Most trials had 6-month follow-up; a few had 1- or 2-year follow-up. Evidence was insufficient to draw conclusions about the effectiveness of aerobic training, resistance training, or tai chi for improving cognition. Low-strength evidence showed that multicomponent physical activity interventions had no effect on cognitive function. Low-strength evidence showed that a multidomain intervention comprising physical activity, diet, and cognitive training improved several cognitive outcomes. Evidence regarding effects on dementia prevention was insufficient for all physical activity interventions(4).
A randomised trial of over 1600 participants evaluated cognitive outcomes and found no improvement following PA interventions. At 24 months, the mean Digit Symbol Coding task scores were 46.26 points for the physical activity group vs 46.28 for the health education group (mean difference, -0.01 points [95% CI, -0.80 to 0.77 points], P = .97). The mean Hopkins Verbal Learning Test delayed recall scores were 7.22 for the physical activity group vs 7.25 for the health education group (mean difference, -0.03 words [95% CI, -0.29 to 0.24 words], P = .84). Incident MCI or dementia occurred in 98 participants (13.2%) in the physical activity group and 91 participants (12.1%) in the health education group (odds ratio, 1.08 [95% CI, 0.80 to 1.46])(6).
The FINGER trial a 2-year multidomain intervention of diet, exercise, cognitive training, and vascular risk monitoring versus control to prevent cognitive decline in at-risk elderly people assessed 2654 participants’ cognitive function. Findings from this large, long-term, randomised controlled trial suggest that a multidomain intervention could improve or maintain cognitive functioning in at-risk elderly people from the general population(5).
Quality of Evidence
Grade B – Moderate
Strength of Recommendation
1 – Strong
Conclusion
Moderate to high quality evidence shows that physical activity particularly as part of a multi-modal lifestyle intervention can have positive outcomes on cognitive decline. Further trials are needed. The current evidence has high heterogeneity and outcomes are not uniformly consistent. The recommendation is to maintain a healthy lifestyle including moderate-vigorous physical activity to help prevent cognitive decline.
References
- Livingston G, Huntley J, Sommerlad A, Ames D, Ballard C, Banerjee S, et al. Dementia prevention, intervention, and care: 2020 report of the Lancet Commission. Lancet [Internet]. 2020 Aug 8 [cited 2022 Jul 22];396(10248):413–46. Available from: http://www.thelancet.com/article/S0140673620303676/fulltext
- Sofi F, Valecchi D, Bacci D, Abbate R, Gensini GF, Casini A, et al. Physical activity and risk of cognitive decline: a meta-analysis of prospective studies. J Intern Med [Internet]. 2011 Jan 1 [cited 2022 Jul 22];269(1):107–17. Available from: https://onlinelibrary.wiley.com/doi/full/10.1111/j.1365-2796.2010.02281.x
- Hamer M, Chida Y. Physical activity and risk of neurodegenerative disease: a systematic review of prospective evidence. 2009 Feb 1 [cited 2022 Jul 22];39(1):3–11. Available from: https://pubmed.ncbi.nlm.nih.gov/18570697/
- Brasure M, Desai P, Davila H, Nelson VA, Calvert C, Jutkowitz E, et al. Physical activity interventions in preventing cognitive decline and alzheimer-type dementia a systematic review. Ann Intern Med. 2018 Jan 2;168(1):30–8.
- Ngandu T, Lehtisalo J, Solomon A, Levälahti E, Ahtiluoto S, Antikainen R, et al. A 2 year multidomain intervention of diet, exercise, cognitive training, and vascular risk monitoring versus control to prevent cognitive decline in at-risk elderly people (FINGER): a randomised controlled trial. Lancet [Internet]. 2015 Jun 6 [cited 2022 Jul 22];385(9984):2255–63. Available from: http://www.thelancet.com/article/S0140673615604615/fulltext
- Sink KM, Espeland MA, Castro CM, Church T, Cohen R, Dodson JA, et al. Effect of a 24-Month Physical Activity Intervention vs Health Education on Cognitive Outcomes in Sedentary Older Adults: The LIFE Randomized Trial. JAMA [Internet]. 2015 Aug 25 [cited 2022 Oct 14];314(8):781–90. Available from: https://pubmed.ncbi.nlm.nih.gov/26305648/