Background: Several studies have reported that aerobic exercise can favorably affect memory. However, studies on this effect in memory-impaired older adults are limited and primarily rely on retrospective data. Baker and colleagues conducted a randomized controlled trial examining the effect of aerobic exercise in sedentary older adults diagnosed with mild cognitive impairment.

The Study: The intervention group started a supervised exercise program for 45 to 60 minutes per session, four days per week, using treadmills, stationary bicycles, or elliptical trainers. Exercise duration and intensity were gradually increased during the first six weeks until participants were exercising at 75 to 85 percent of their heart rate reserve. The control group was assigned a regimen of stretching and balance exercises on the same schedule as the intervention group, maintaining their heart rate at 50 percent or less of their heart rate reserve. Cognitive function was assessed using standardized testing at baseline and was reevaluated at three and six months. Patients were excluded for unstable heart disease, cerebrovascular disease, or musculoskeletal impairment.

Results: Seventeen women and 16 men were followed. Compared with the control group, the aerobic exercise group had significantly improved executive control processes (e.g., multitasking, information processing, selective attention) and verbal fluency on validated test tools. Women exhibited more benefit than men, with men only improving on one test of executive function (trail making). Verbal declarative memory (e.g., list learning, ability to recall stories) was unaffected by aerobic exercise.

Conclusion: The authors conclude that aerobic exercise improves cognitive function in older adults with mild cognitive impairment. In this study, women had greater cognitive improvement than men, despite similar improvements in cardiorespiratory fitness.