Aerobic Exercise May Reverse Aging Effects Related to Alzheimer’s Disease

Ana de Barros, PhD avatar

by Ana de Barros, PhD |

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Results from a recent study presented at the 8th International Conference on Clinical Trials for Alzheimer’s Disease (CTAD) revealed that aerobic exercise improves brain function and reduces neurodegeneration markers in older adults at risk for Alzheimer’s disease (AD). Study results also indicate that aerobic exercise may be a potential disease-modifying intervention for people in the earliest stages of AD, according to lead researcher Laura Baker, PhD, a cognitive neuroscientist at Wake Forest Baptist Medical Center.

Researchers assessed beta amyloid and tau protein levels, two proteins in the cerebrospinal fluid (CSF), as evidence has shown that in neurodegenerative processes such as those occurring in AD, there is an increase in tau CSF levels and a decline in beta amyloid levels, as the latter is deposited as plaques in the brain. The practice of aerobic exercise appears to reverse this process, especially in older adults who present higher levels of cognitive impairment. “We don’t know yet if we are reversing the process, protecting the brain, or just buying some time,” Dr. Baker said in a press release.

The team enrolled adults age 55 to 89 who had mild cognitive impairment (MCI) and prediabetes to explore the effects of aerobic exercise in the brain. Participants were randomized into a structured exercise program comprising either moderate-to-high intensity aerobic exercise or stretching exercises for 45-60 minutes. All participants completed the exercise routine four times per week for a period of six months.

At baseline and at the end of the intervention, all participants had their CSF and bloods collected and were asked to complete tests assessing body fat, glucose tolerance, cognition and how long it took to walk 400 meters. Magnetic resonance imaging (MRI) scans were performed in 40 study participants.

The results revealed that participants in the aerobic exercise group had higher cognitive scores, faster walk times, and an improvement in their glucose tolerance. Moreover, aerobic exercise had a beneficial effect on the levels of tau and beta amyloid proteins in the CSF and led to a significant increase in blood flow to certain areas of the brain when participants were at rest. “Resting blood flow was increased in those areas of brain where blood flow is typically decreased with aging and with the onset and progression of MCI due to Alzheimer’s disease,” Dr. Baker explained.

The brain imaging group at Wake Forest is now analyzing these data further to learn more about how brain cells change their communication patterns in response to exercise. “The question we are going to ask next is whether the increased blood flow reflects improved health of the vessels in specific regions of the brain, or increased volume of blood to these regions,” Dr. Baker said.

In the study’s next phase, researchers will prolong the exercise program to 18 months, and the study will be conducted under the auspices of the Alzheimer’s Disease Cooperative Study (ADCS) across 14 country sites. For the first 12 months participants will be supervised by a trainer at their local YMCA,  followed by a six-month unsupervised period that will assess the validity of the intervention.

Dr. Baker said she is hopeful that these results will motivate people to think about exercise in a different way. “We all know that exercise is good for us, but maybe seeing observable, objective brain changes will provide the impetus to get us out the door to exercise,” she said.