Exercise stalled cognitive decline among adults with mild cognitive impairment

Both moderate aerobic exercise and stretching and balance activities protected against cognitive decline in older adults with mild cognitive impairment, according to research at the Clinical Trials on Alzheimer’s Disease annual meeting.

Laura D. Baker, PhD, professor of gerontology and geriatric medicine at Wake Forest University School of Medicine, and colleagues aimed to test whether 12 months of supervised moderate intensity aerobic exercise protected against cognitive decline compared with low intensity stretching and balancing.

Researchers conducted the EXERT trial at 14 sites and enrolled 296 participants, who were randomized to perform aerobic exercise or stretching, balancing and range-of-motion activities for 18 months. Exercise was supervised during the first 12 months of participation, whereas the last 6 months were unsupervised.

“We tested the effects of physical exercise on cognitive function using a new global composite score, referred to as the ADAS-Cog-Exec,” Baker said during the presentation. “This composite score was developed to be more sensitive to subtle changes in mild cognitive impairment and includes select subtests on the ADAS-Cog-13, additional tests of executive function and select test on the [clinical dementia rating] box scores that are more sensitive to subtle changes in [mild cognitive impairment].”

Study participants were evaluated at baseline and at months 6, 12 and 18. In addition to tests for cognitive function, researchers collected blood for AD biomarker analysis; participants also underwent brain MRI.

For those in the moderate aerobic exercise group, 81% of expected supervised sessions were completed, while those in the low-intensity exercise group completed 87% of sessions. At baseline, participants had mild cognitive impairment (mean Mini-Mental State Examination score = 27.9; mean Clinical Dementia Rating Sum of Boxes = 1.5), and 25% were APOE4 carriers.

“[There was] no difference between the high intensity and low intensity on ADAS-Cog,” Baker said. “Importantly, we also saw no decline. Over time, there was no decline from baseline to month 12 for either group of these amnestic [mild cognitive impairment] individuals.”

According to researchers, the study was the longest exercise trial to date in which mild cognitive impairment was assessed. They acknowledged that the long trial duration, with “greater volume” of exercise, possibly provided more protection, regardless of intensity, and that socialization among participants also may have protected against decline.