MRI shows physical exercise could slow cognitive decline

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A brain imaging study has found that physical exercise, as opposed to participating in social or mental activities, may be the best way to slow cognitive decline as people age.

In the study, published Oct. 22 in the journal Neurology, researchers led by Alan Gow, Ph.D., a senior research fellow from the University of Edinburgh, followed up on a longitudinal aging study in Scotland called the Lothian Birth Cohort Study. Under that study children born in 1936 were given intelligence tests 11 years later and have been periodically reassessed since then.

The new study analyzed 638 subjects from the Lothian study who filled out a lengthy health survey detailing the leisure and physical activities they participated in when they were 70 years old. When they were 73, they were given MRIs that showed that higher levels of exercise were associated with less brain atrophy.

"People in their seventies who participated in more physical exercise, including walking several times a week, had less brain shrinkage and other signs of aging in the brain than those who were less physically active," Gow said in an announcement. "On the other hand, our study showed no real benefit to participating in mentally and socially stimulating activities on brain size, as seen on MRI scans, over the three-year time frame."

According to an article on LiveScience,  Gow and his colleagues could neither come up with a biological reason why physical exercise contributes to a healthier brain, nor rule out the possibility that those subjects with a healthy brain simply exercise more than subjects showing cognitive decline.

"To be definitive, we do of course need more large-scale trials examining the effects of physical activity interventions," Gow said. According to an article in the Wall Street Journal, now that the participants have reached the age of 76, they are undergoing a second MRI scan, which will allow the researchers to see how well the link between brain health and exercise holds up.

For more:
- see the study abstract
- read the announcement
- check out the article on LiveScience
- read the WSJ article

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