It’s well-established that exercise has a great effect on your brain: It boosts brain function in those at risk for Alzheimer’s, boosts brainpower in children, and generally just improves memory. But how fitness affects mental activity has never been directly shown—until now, as a study from the University of Tsukuba in Japan has linked brain activation to mental and physical performance.
As reported in Neuroimage, the researchers discovered that older Japanese men who were fit not only performed better than less fit men. More exciting, though, is that we usually shift which parts of our brain we use to perform the same mental tasks with age—but the fit men also used their brain in the same way as young men.
The specific task given is what’s known as a Stroop test—which in this case involved the participants seeing something along the lines of this:
The test required that they report the color of the letters as opposed to the color spelled out in each word.
The time it takes an individual to determine the colors is a common measurement of brain function, and is a task completed by the prefrontal cortex (PFC). In young adults, this is done in the left PFC, but for aging adults, both the left and right sides activate.
This change is known as HAROLD (hemispheric asymmetry reduction in older adults), and reflects adaptations of the brain necessary to make up for reduced brain capacity and efficiency caused by age-related structural and physiological decline.
The participants—60 older men (aged 64-75 years)—had their brain activity measured while completing this task using functional near infrared spectroscopy, or fNIRS. fNIRS measures blood oxygen concentration in surface blood vessels—a reflection of brain activity, as active brain cells require more oxygen.
Their reaction times were measured as well, and their aerobic fitness levels were tested by measuring their heart rates and ratings of perceived exertion while using an ergometer.
The results?
The men who were more fit had faster reaction times as compared to less fit men. But, more excitingly, they favored the left side of the PFC for performing the Stroop tests—like young adults do—indicating that exercise may play a role in keeping the brain “youthful”.
The exact reasoning behind how this happens isn’t yet clear, but study leader Dr. Hideaki Soya believes he may have an idea: “One possible explanation suggested by the research is that the volume and integrity of the white matter in the part of brain that links the two sides declines with age. There is some evidence to support the theory that fitter adults are able to better maintain this white matter than less fit adults, but further study is needed to confirm this theory,” he said in a statement.
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Feature Image: Thinkstock
Story Image: Stroop-interference-related cortical activation patterns are shown. Credit: University of Tsukuba
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