Regular Exercise Appears to Slow Cognitive Decline in MCI

Regular exercise, regardless of intensity level, appears to slow cognitive decline in sedentary older adults with mild cognitive impairment (MCI), new research from the largest study of its kind suggests.

Topline results from the EXERT trial showed patients with MCI who participated regularly in either aerobic exercise or stretching/balance/range-of-motion exercises maintained stable global cognitive function over 12 months of follow-up — with no differences between the two types of exercise.

"We're excited about these findings, because these types of exercises that we're seeing can protect against cognitive decline are accessible to everyone and therefore scalable to the public," study investigator Laura Baker, PhD, Wake Forest University School of Medicine, Winston-Salem, North Carolina, said at a press briefing.

The topline results were presented at the Alzheimer's Association International Conference (AAIC) 2022.

No Decline

The 18-month EXERT trial was designed to be the definitive study to answer the question about whether exercise can slow cognitive decline in older adults with amnestic MCI, Baker reported.

Investigators enrolled 296 sedentary men and women with MCI (mean age, about 75 years). All were randomly allocated to either an aerobic exercise group (maintaining a heart rate at about 70% to 85%) or a stretching and balance group (maintaining heart rate < 35%).

Both groups exercised four times a week for about 30 to 40 minutes. In the first 12 months they were supervised by a trainer at the YMCA and then they exercised independently for the final 6 months.

Participants were assessed at baseline and every 6 months. The primary endpoint was change from baseline on the ADAS-Cog-Exec, a validated measure of global cognitive function, at the end of the 12 months of supervised exercise.

During the first 12 months, participants completed over 31,000 sessions of exercise, which is "quite impressive," Baker said.

Over the first 12 months, neither the aerobic group nor the stretch/balance group showed a decline on the ADAS-Cog-Exec.

"We saw no group differences, and importantly, no decline after 12 months," Baker reported.

Supported Exercise "Crucial"

To help "make sense" of these findings, Baker noted that 12-month changes in the ADAS-Cog-Exec for the EXERT intervention groups were also compared with a "usual care" cohort of adults matched for age, sex, education, baseline cognitive status, and APOE4 genotype.

In this "apples to apples" comparison, the usual care cohort showed the expected decline or worsening of cognitive function over 12 months on the ADAS-Cog-Exec, but the EXERT exercise groups did not.

Baker noted that both exercise groups received equal amounts of weekly socialization, which may have contributed to the apparent protective effects on the brain.

A greater volume of exercise in EXERT compared with other trials may also be a factor. Each individual participant in EXERT completed more than 100 hours of exercise.

"The take-home message is that an increased amount of either low intensity or high intensity exercise for 120 to 150 minutes per week for 12 months may slow cognitive decline in sedentary older adults with MCI," Baker said.

"What's critical is that this regular exercise must be supported in these older [patients] with MCI. It must be supervised. There has to be some social component," she added.

In her view, 120 minutes of regular supported exercise for sedentary individuals with MCI "needs to be part of the recommendation for risk reduction."

Important Study

Commenting on the findings for Medscape Medical News, Heather Snyder, PhD, vice president of medical and scientific relations at the Alzheimer's Association, noted several studies over the years have suggested that different types of exercise can have benefits on the brain.

"What's important about this study is that it's in a population of people that have mild cognitive impairment and are already experiencing memory changes," Snyder said.

"The results suggest that engaging in both of these types of exercise may be beneficial for our brain. And given that this is the largest study of its kind in a population of people with MCI, it suggests it's 'never too late' to start exercising," she added.

Snyder noted the importance of continuing this work and to continue following these individuals "over time as well."

The study was funded by the National Institutes of Health, National Institute on Aging. Baker and Snyder have disclosed no relevant financial relationships.

Alzheimer's Association International Conference (AAIC) 2022: Abstract 69700. Presented August 2, 2022.

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