Exercise and Your Memory

If scientific studies suggesting that regular exercise helps to prevent heart disease and strokes and even Type 2 diabetes haven’t been enough to get you off of your sofa and out exercising, new research adds another reason – exercise may improve your memory.

Exercise improves our ability to recognize objects

In a recent study published in Neuroscience, researchers at Dartmouth College tested young adults who were healthy but who generally lived a sedentary lifestyle, and didn’t exercise regularly. The subjects filled out questionnaires and had blood samples taken for genetic testing (more on this and the role of BDNF later in this article), and then were given object recognition tests to see how well they could recall images they had been shown earlier.

Subjects were then assigned randomly to groups that either exercised regularly (walking or jogging for at least 30 minutes, four times a week), or that didn’t exercise, and maintained their sedentary lifestyle. At the end of the month, all subjects were given the same object-recognition tests. The sedentary group showed no significant change in their scores, whereas the group that had exercised improved their scores.

Another study conducted in Ireland found similar results. In this study, college-aged men with sedentary lifestyles were shown a series of photos containing the names and faces of people they’d never met before. After a break, they were asked to recall the names of these people as just their faces were shown to them.

Immediately after these tests, half of the subjects were asked to ride a stationary bicycle for 30 minutes, while the other half sat quietly. Then both groups took the same memory test again, with different names and faces this time. The subject who had exercised performed significantly better on the second test than they had on the first test, while those who had not exercised did not improve their scores.

What does all this mean?

The honest answer is that the researchers don’t know for sure yet, because their results are preliminary and more tests need to be performed. But the preliminary data suggests that there is a strong link between exercise and improving one’s memory.

The memory improvements were cumulative, in that the most improvements were seen in those who had been most consistent with exercising regularly over a period of time. But surprisingly in both studies there were immediate improvements in memory test scores even among subjects who were part of the “sedentary group” but who were then asked to exercise immediately before being retested. So in a sense, even “short-term exercise” improved their short-term memory.

The fascinating role of BDNF

One of the factors examined in both of these studies is the role of a protein called brain-derived neurotropic factor, or BDNF. Numerous tests have shown that production of BDNF increases after exercise, and increased levels of this protein have been linked to positive changes in the brain, including improved short-term memory, better ability to recognize objects seen previously, and overall improvement in mental functioning. The role of BDNF in causing all of these positive changes in brain chemistry is not yet fully understood, just the fact that exercise increases production of it.

But not for everyone. There is a common genetic variant, found in 30 percent of people of European Caucasian heritage, that “blunts” or prevents BDNF production after exercise. In the Dartmouth College study, researchers tested each of the subjects for this variant, and correlated it with their data. What they found was that while most of the subjects were able to improve their scores on object-recognition tests after exercise, subjects with the BDNF variant did not. Their memories were not improved by exercise.

So although the case for exercise improving memory and brain functioning looks promising, the results of these studies are still preliminary, and many questions still remain to be answered. Until they are, the smart approach may be to exercise anyway, because even if it doesn’t make you smarter, at least you’ll be healthier.

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Juliette Siegfried, MPH

Juliette Siegfried, MPH, has been involved in health communications since 1991. Shortly after obtaining her Master of Public Health degree, she began her career at the National Institutes of Health in Bethesda, Maryland. Juliette now lives in Europe, where she launched ServingMed(.)com, a small medical writing and editing business for health professionals all over the world.

Juliette's resume, facebook: juliette.siegfriedmph, linkedin: juliettes, (+31) 683 673 767

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