Effects of physical exercise on cognitively impaired older adults: a systematic review

Background. The main aim of this study was to estimate the effect of physical activities (PA) on cognitive functions (CF) in cognitively impaired older adults divided according to the impairment severity. Methods. We searched Web of Science, Scopus, and PubMed for randomized controlled trials (RCT). We focused on the effect of exercise on CF in intervention groups and control groups separately in people with cognitive impairment across three levels - borderline intact, mild, and moderate cognitive impairment separately. Results. Data from 40 studies involving 1,780 participants from intervention groups and 1,508 participants from control groups were analyzed. 37.0% of intervention groups presented a statistically significant beneficial effect of PA on CF, while 5% presented a statistically significant harmful effect of PA on CF. 40.0% of the control groups showed a significant decrease in CF. 54.3% interventions had a statistically significant beneficial effect (Hedges’ g > 0). However, there was a great variability between the studies in terms of exercise program description and cognitive impairment of the subjects. Conclusions. Physical exercise was associated with cognitive function improvement in older people with cognitive impairment. The positive effect is stronger in people with a mild level of cognitive impairment.