Effects of Exercise on Cognitive Performance in Older Adults: A Narrative Review of the Evidence, Possible Biological Mechanisms, and Recommendations for Exercise Prescription
Table 1
Meta-analyses of RCTs evaluating the impact of exercise interventions on cognition.
(i) AE improved executive functioning relative to controls () (ii) AE interventions benefitted global cognitive function and executive functions more than RE (iii) Combined training benefitted global cognitive function and episodic memory more than AE and RE
(i) Date range 1966–2001 (ii) Measure of aerobic fitness
AE (49% of participants) or combined AE + RE (51% of participants)
Frequency: NR Intensity: NR Duration: 1–3 months (38%), 4–6 months (36%) 6+ months (26.7%)
NR
(i) Exercise had the greatest effect on executive function () (ii) Combined training produced larger improvements in cognition than AE alone ( vs. 0.41) (iii) Long-term training associated with largest improvements in cognition ()
(i) Moderate effect of chronic exercise on cognition () (ii) Effect of clinical trials on cognition () (iii) Exercise session duration, frequency, and program duration were not significant moderators of cognition
Frequency: 1–5 sessions/wk Session duration: 45–120 mins Duration:1–6 months
Active and inactive
(i) Yoga had a moderate effect () on cognition (ii) Largest effect on attention and processing speed () followed by executive function () and memory ()
Healthy older adults with no cognitive impairment 50+ years
(i) Cardiovascular disease, other medical, psychiatric, or neurological conditions were excluded (ii) Date range 2002–2012
AE (n = 19), RE (n = 7), Tai chi (n = 3)
Frequency: 1–3 sessions/wk Intensity: variable Total duration: single bout to 1 year
No exercise, nonaerobic exercise, education, social or mental activities
(i) No improvements in AE vs stretching/toning on cognition (ii) Significant improvements for RE vs. stretching/toning in reasoning () and Tai chi vs no exercise in attention () and processing speed ()
Older adults with and without cognitive impairment 50+ years
(i) Neurological and mental health populations excluded (ii) Unsupervised exercise interventions excluded (iii) Interventions <4 weeks excluded
AE (n = 18), RE (n = 13, multicomponent (n = 10), Tai chi (n = 4), yoga (n = 2)
Frequency: 1–5 sessions/wk Session duration: 20–90 min Intensity: variable, many NR Total duration: 6–52 weeks
Active (stretching, balance and tone, sham cognitive training, health education) and inactive (social interaction), no contact
(i) Improved cognitive function (SMD = 0.29; ) with exercise of all types (ii) AE, RE, combined, and Tai chi interventions had significant effect estimates () (iii) Session duration >45 min ≤ 60 min associated with improved cognition () (iv) Moderate () and vigorous () intensity exercise (not low-intensity) associated with improved cognition
Frequency: 1–5 sessions/wk (mean = 2.62) Program duration: 4–52 weeks (mean = 22.3 weeks) Mean total dose: 2720 mins
Active and passive controls
(i) Small positive effect of exercise on executive function (d = 0.27) and memory (d = 0.24) in healthy older adults (ii) Exercise dose (type, session, duration, program duration, frequency, intensity) did not predict changes in cognition (iii) Shorter exercise sessions and higher frequency sessions predicted larger effects in those with cognitive impairment
Sedentary healthy older adults 55+ years and older adults with cognitive impairment
(i) Published in English
AE (n = 8)
Frequency:1–7 sessions/wk Session duration: 30–60 mins Program duration: 4 weeks–1 year
Active and passive controls
(i) Walking improved set-shifting and inhibition in sedentary older adults without cognitive impairment (d = 0.36) (ii) No effect of walking on executive function among older adults with cognitive impairment (d = 0.14)
Healthy adults and MCI Mean age 18+ years 23 RCTs with older adults
(i) Treatment duration: >1 month
Supervised AE (n = 29)
Frequency: 1–5 sessions/wk Intensity: variable, many NR Duration: 8–72 weeks
Nonaerobic exercise, waitlist, education, stretching, social activities
(i) Modest improvements in attention and processing speed (), executive function () (ii) Exercise intensity and duration did not moderate effects on memory (iii) Older adults demonstrated larger improvements in working memory compared to younger participants
(i) Improvements in global cognition compared with controls (mean difference = 0.92), particularly cognitive flexibility, working memory, verbal fluency, and learning (ii) Moderate dose (60–120 mins per week) significantly improved global cognition compared to controls
Frequency: 1–5 sessions per week Intensity: variable Duration: 8–26 weeks
No treatment, nonaerobic exercise, social or mental activities
(i) No benefit of AE vs active or inactive controls on any of the 11 cognitive domains (ii) Incresed fitness did not coincide with improvements in cognition.
(i) Benefits global cognition (), executive functions (), learning and memory (), and language () (ii) Mind-body exercise more effective for older adults without cognitive impairment (iii) Total training time predictor of global cognition, executive function, and language
RCT, randomized controlled trial; MCI, mild cognitive impairment; NR, not reported; min, minutes; AE, aerobic exercise; RE, resistance exercise.
