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In people with mild cognitive impairment, exercise improves cognitive function

Song D, Yu DSF, Li PWC, et al. The effectiveness of physical exercise on cognitive and psychological outcomes in individuals with mild cognitive impairment: A systematic review and meta-analysis. Int J Nurs Stud. 2018;79:155-64.

Review question

In people with mild cognitive impairment, can exercise improve cognitive function (e.g., thinking, learning, and remembering)?

Background

Mild cognitive impairment includes problems with thinking, memory, language, and judgment that are noticeable but don’t much affect daily living. People with mild cognitive impairment are at risk for developing dementia, which is cognitive impairment that is serious enough to interfere with daily living.

How the review was done

The researchers did a systematic review of studies available up to October 2017. They found 11 randomized controlled trials that included 929 people.

The key features of the studies were

• people were at least 50 years of age and were diagnosed with mild cognitive impairment;
• 6 studies evaluated aerobic exercise, 3 evaluated resistance training, and 2 evaluated 3 or 4 exercise types (including aerobic exercise, resistance training, stretching and balance, and Tai Chi);
• people exercised for 6 weeks to 1 year; and
• exercise was compared with stretching, health education, or social visits or activities.

What the researchers found

Exercise

• improved overall cognition; but
• did not improve memory or executive function (that is, mental skills needed for planning, problem solving, and focusing attention).

Conclusion

In people with mild cognitive impairment, exercise improved overall cognition but not memory or executive function.

Exercise for improving cognitive functioning in people with mild cognitive impairment

*Based on standard mean differences (SMD); very small = less than 0.2 SMD, small = 0.2 to 0.49 SMD, medium = 0.5 to 0.79 SMD, large = 0.8 or more SMD.