A moderate-intensity walking regimen may reduce symptoms of mild vascular cognitive impairment (VCI), a small Canadian study suggests.
Participants with vascular cognitive impairment, sometimes called vascular dementia, who walked three hours per week for six months had improved reaction times and other signs of improved brain function, the Canadian team reports.
Vascular cognitive impairment (VCI) refers to mildly impaired thinking or more advanced dementia that’s due to the same kinds of blood vessel damage seen with heart disease elsewhere in the body. It is the second most common cause of dementia after Alzheimer’s disease. “It is well established that regular aerobic exercise improves cardiovascular health and cerebrovascular health,” the study’s senior author Teresa Liu-Ambrose is quoted in the report as saying.
“More specifically, it reduces one’s risk of developing chronic conditions such as high blood pressure, diabetes (type II), and high cholesterol. These chronic conditions have a negative impact on the brain – likely through compromised blood flow to the brain,” said Liu-Ambrose, a researcher with the Aging, Mobility, and Cognitive Neuroscience Lab at the University of British Columbia in Vancouver.
The brain is a highly metabolic organ and to keep it healthy, it requires good blood flow to deliver the necessary nutrients and oxygen to its tissues, she added. “It is worth noting that in our study, reduced blood pressure (secondary to exercise) was associated with improved cognitive function,” Liu-Ambrose said.
Aerobic exercise may also benefit the brain by increasing growth factors, which are substances made by the body that promote cell growth, differentiation and survival, she said.
Liu-Ambrose and colleagues randomly assigned 38 older adults with mild VCI to one of two groups. One group followed an aerobic training programme consisting of three one-hour walking classes each week for six months, while the other group continued with their usual care. In addition, both groups were given information about vascular cognitive impairment and tips for eating a healthier diet.
Before the exercise programme began and at the end of six months, all the participants also had functional MRI brain scans and other tests that measured neural activity and cognitive ability.
People in the aerobic training group had significant improvements in their reaction times on the cognitive tests, and showed changes in their brain activity that made them resemble healthy brains more. The comparison group showed no changes.
Overall, exercise appears to be a promising strategy for promoting cognitive health in older adults, Liu-Ambrose said.
“While more research is needed to better understand how it brings about its benefits and what factors may impact the degree of benefit observed, there is minimal negative consequence of exercising,” she said.
Liu-Ambrose said she doesn’t know if exercise can actually prevent VCI because there have been no studies to determine that. “However, population based studies do suggest that physical activity does reduce the risk of developing VCI. Moreover, as mentioned earlier, aerobic exercise is very effective in reducing vascular risk factors associated with VCI, such as high blood pressure.”
The study was small, and because participants had to be able to walk for up to an hour, it’s possible they were physically healthier than average, the authors note. The socialising involved in the walking classes might have also had some effect, they add.
“Given the small sample size, one needs to be cautious about interpreting the results of this pilot study. However, it is encouraging to see that the six-month aerobic exercise programme improved certain aspects of cognition and showed changes on functional brain imaging,” said Dr Joe Verghese, director of the Montefiore Einstein Centre for the Aging Brain at Montefiore Medical Centre in New York.
“The effect of exercise in this, and other studies seems to be on improving executive functions, which are required for planning, thinking and judgment,” Verghese, who wasn’t involved in the study, said. “The findings, if confirmed in larger studies, may have implications in advising exercise in older patients with vascular risk factors for brain protection,” Verghese said.
Abstract
Background: Vascular cognitive impairment (VCI) results from cerebrovascular disease, and worldwide, it is the second most common type of cognitive dysfunction. While targeted aerobic training is a promising approach to delay the progression of VCI by reducing cardiometabolic risk factors, few randomised controlled trials to date have specifically assessed the efficacy of aerobic training on cognitive and brain outcomes in this group at risk for functional decline.
Aim: To examine the effect of moderate-intensity aerobic training on executive functions and functional neural activity among older adults with mild subcortical ischaemic VCI (SIVCI).
Methods: Older adults with mild SIVCI were randomly assigned to: (1) 6-month, 3×/week aerobic training (n=10) or (2) usual care (control; n=11). Participants completed functional MRI (fMRI) at baseline and trial completion. During the fMRI sessions, behavioural performance on the Eriksen flanker task and task-evoked neural activity were assessed.
Results: At trial completion, after adjusting for baseline general cognition, total white matter lesion volume and flanker performance, compared with the control group, the aerobic training group significantly improved flanker task reaction time. Moreover, compared with the controls, the aerobic training group demonstrated reduced activation in the left lateral occipital cortex and right superior temporal gyrus. Reduced activity in these brain regions was significantly associated with improved (ie, faster) flanker task performance at trial completion.
Summary: Aerobic training among older adults with mild SIVCI can improve executive functions and neural efficiency of associated brain areas. Future studies with greater sample size should be completed to replicate and extend these findings.
Authors
Chun Liang Hsu, John R Best, Jennifer C Davis, Lindsay S Nagamatsu, Shirley Wang, Lara A Boyd, GY Robin Hsiung, Michelle W Voss, Janice Jennifer Eng, Teresa Liu-Ambrose
[link url="https://www.yahoo.com/news/walking-linked-improved-brain-function-161235229.html"]Yahoo News report[/link]
[link url="http://bjsm.bmj.com/content/early/2017/04/21/bjsports-2016-096846"]British Journal of Sports Medicine abstract[/link]