Blood flow to the brain reduces just ten days after stopping exercise

Blood flow to the brain reduces just ten days after stopping exercise

Healthy, physically fit older people, who stop exercising for a period of just 10 days, are at risk of decreasing blood flow to their brain and therefore affecting memory and learning ability, a new study shows.
The study, led by the University of Maryland (UMD) School of Public Health, is one of a growing number of studies that strengthens the relationship between cognitive functioning and physical activity.
Exercise in older people has been shown to protect the hippocampus – a vital portion of the brain – from shrinking. Studies on mice have also shown that regular exercise can stimulate growth of new blood vessels and brain cells.
The team of researchers led by J. Carson Smith, associate professor of kinesiology at UMD, set out to examine the relationship between less exercise and brain functioning, with a focus on blood flow in the hippocampus. The researchers explained that the hippocampus is a portion of the brain that is most affected by old age.
The team used Magnetic Resonance Imaging (MRI) scans on the brains of healthy, fit adults aged between 50 and 89 years, before and after a 10-day hiatus from exercise.
This allowed the researchers to measure the velocity of the blood flowing into portions of the brain during peak physical fitness, and again after 10 days without exercising. A significant decrease in blood flow to certain areas of the brain was discovered, with the left and right hippocampus being most significantly affected.
Despite these findings, no substantial decrease in cognitive function was discovered, with verbal fluency tests being scored similarly to those done before the exercise hiatus. The participants who took part in this study were all high level athletes, and were described by the research team as “a unique population and should not be considered equivalent to older adults who engage in regular moderate to vigorous intensity leisure-time physical activity.”
On average these participants were each running 36 miles per week, equivalent to nine miles per day four days a week. It is not surprising that these volunteers had a V02 max in the top 10 per cent for their age when looking at their exercise regime. V02 max refers to the maximum amount of oxygen that can be consumed during exercise, and is one of the markers used to assess fitness levels.
Dr Smith said: “We know that if you are less physically active, you are more likely to have cognitive problems and dementia as you age. However, we did not find any evidence that cognitive abilities worsened after stopping exercising for just 10 days.
“But the take home message is simple – if you do stop exercising for 10 days, just as you will quickly lose your cardiovascular fitness, you will also experience a decrease in blood brain flow.”
The researchers explained that their results show a need to further examine how quickly brain blood flow changes occur and how quickly long term effects can set in.
The study was published in the journal Frontiers in Aging Neuroscience.

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