Aerobic exercise preserves brain volume and improves cognitive function
Using a new MRI technique, researchers found adults with mild cognitive impairment (MCI) who exercised 4 times a week over a 6-month period experienced an increase in brain volume in specific, or local, areas of the brain, but adults who participated in aerobic exercise experienced greater gains than those who just stretched. The study included 35 adults with MCI participating in a randomized, controlled trial of exercise intervention. Individuals with MCI are at risk of developing Alzheimer’s disease (AD) which affects >5 million Americans today.
The participants were divided into two groups. 16 adults (average age 63 years) engaged in aerobic activity, including treadmill, stationary bike or elliptical training, four times per week for six months. A control group of 19 adults (average 67 years) participated in stretching exercises with the same frequency. High-resolution brain MR images were acquired from all participants before and after 6-months. The MRI results were compared using conventional and biomechanical metrics to measure the change in both brain volume and shape.
“We used high-resolution MR images to measure anatomical changes within areas of the brain to obtain both volumetric data and directional information,” said Jeongchul Kim, Ph.D. For both the aerobic and stretching groups, brain volume increased in most gray matter regions, including the temporal lobe, which supports short-term memory.”Compared to the stretching group, the aerobic activity group had greater preservation of total brain volume, increased local gray matter volume and increased directional stretch of brain tissue,” Dr. Kim said.
Among the stretching group, analysis revealed a local contraction, or atrophy, within the white matter connecting fibers. According to Dr. Kim, such directional deformation, or shape change, is partially related to volume loss, but not always. “Directional changes in the brain without local volume changes could be a novel biomarker for neurological disease,” he said. “It may be a more sensitive marker for the tiny changes that occur in a specific brain region before volumetric changes are detectable on MRI.”
He said both MRI measures are important to the treatment of MCI and AD, which require careful tracking of changes in the brain while patients engage in interventions including diet and exercise to slow progression of the disease. Participants in the aerobic exercise group showed statistically significant improvement in executive function, whereas the stretching group did not improve.
“Any type of exercise can be beneficial,” Dr. Kim said. “If possible, aerobic activity may create potential benefits for higher cognitive functioning.” https://www.eurekalert.org/pub_releases/2016-11/rson-aep111716.php
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