How Exercise Enhances Brain Function
Researchers have long linked the role that exercise plays in keeping your brain healthy. And two new studies provide fresh evidence that any level of exercise has a positive effect on brain health — including a better memory and improved problem-solving, attention span and reaction time.
In what is the largest study to date, an international collaboration of researchers from Canada, Switzerland, and the United States, using genetic data collected from 350,000 people, showed the connection between exercise and how it can sharpen thinking and reduce, or at least stave off, Alzheimer’s and other types of dementia.
The good news is that it doesn’t have to be a lot of exercise. Both vigorous and moderate physical activity boosted cognitive function in the study participants.
And here’s the kicker: the cognitive benefits of moderate physical activity (comparable to jogging) were 50 percent greater than those of vigorous physical activity, suggesting that you don’t need to push yourself to run marathons or tackle triathlons to get the benefits.
The other encouraging news from this study is that the brains of even once-sedentary older people benefit from exercise. In the study, subjects experiencing signs of cognitive decline were able to improve their brain connections and thinking with just a few hours of walking each week.
But to get the maximum brain benefits from exercise, start while you’re young. A Florida Atlantic University study on mice suggests exercising over your lifetime helps the brain build up a reserve of healthy neurons and connections.
Dissecting our DNA
What separates this study from others are the substantial number of participants and the use of a technique called Mendelian randomization, which uses DNA to study behaviors that cause disease.
Researchers looked at the cognitive tests of a group of people born with genes that predispose them to exercise more. While these gene variants have no known effect on cognitive function, the people carrying these “exercise” genes, most of whom did exercise, scored better on cognitive tests, suggesting that their higher levels of exercise made the difference.
“Miracle-Gro” for the brain
Just why is exercise so good for our brains? A new study published in the Journal of Physiology offers some insight.
Exercise increases blood levels of something called brain-derived neurotrophic factor or BDNF, which researchers often refer to as “Miracle-Gro” for the brain. BDNF is a protein released during aerobic exercise which acts like a fertilizer for brain neurons, preventing them from dying and triggering the growth of new brain cells and synapses. In this experiment, 12 healthy young people rode an exercise bike at a leisurely pace for 90 minutes, followed by six minutes of high-intensity intervals. Blood levels of BDNF were measured before, during and after each session. Researchers also tracked levels of lactate; an organic acid released by muscles during exercise. Lactate travels to the brain where, among other things, it prompts the production of BDNF.
While levels of BDNF and lactate rose during the leisurely pedaling, they soared during and after the interval training. Researchers found that BDNF rose by 4 to 5 times and lactate increased sixfold.
The good news here: Any level of exercise is good for your brain. And the more you move and the earlier you start, the bigger the benefits.