Hit the Gym and the Books
When you exercise, your brain needs energy to keep up with your body’s metabolic needs. However, when you finish your workout, neurons, which are your brain cells, remain hungry for more. Japanese scientists investigated this phenomenon and arrived at an interesting conclusion.
The human brain contains millions of cells, called neurons, that form elaborate networks and electric circuits routing and controlling every task we perform in fractions of a second.
The chemical energy your body uses in walking, singing and bench pressing comes from the catabolic breakdown of a simple sugar known as glucose. Stored in the liver and skeletal muscles, a carbohydrate known as glycogen can be broken down into glucose in feedback loops to maintain a homeostatic balance of a stable blood glucose concentration.
Ten years ago, it was discovered that astrocytes, cells that support and nourish neurons, actually contain small stores of glycogen.
When blood glucose levels run low during high energy aerobic exercise (known as hypoglycemia) muscles turn to the breakdown of carbohydrate reserves of glycogen into glucose, which breaks down further in complex biochemical pathways into the chemical energy that fuels the muscle contractions of your legs while running.
During your jog, your brain, which is one of the most “hungry” organs, said Gretchen Reynolds of the New York Times, becomes starved for energy as well, as it is involved in coordinating movements, balance, vision, breathing, among a myriad other factors.
The Japanese researchers from the Laboratory of Biochemistry and Neuroscience at the University of Tsukuba hypothesized that “During prolonged exhaustive exercise that induces hypoglycemia and muscular glycogen depletion, the resultant hypoglycemia may cause a decrease in brain glycogen.”
To test how much the levels of brain glycogen had changed, they had one group of adult male rats run on a treadmill and another group sit on a treadmill sedentarily. From their paper in the Journal of Physiology, the scientists used a high-powered microwave irradiation to instantly freeze the rats’ glycogen levels.
“The food that the rats ate, it appeared, had gone directly to their heads,” said the New York Times, as the rats’ brain glycogen levels “not only had been restored to what they had been before the workout, but had soared past that point, increasing by as much as a 60 percent in the frontal cortex and hippocampus and slightly less in other parts of the brain.”
This apparent “super-compensation” actually became the new norm for brain glycogen levels. As the rats continued exercising over four more weeks, the brain glycogen levels further increased in the frontal cortex and hippocampus, structures that play critical roles in higher-order-thinking and memory.
Limited by our current technology, this study cannot yet be tested on humans. Hideaki Soya, professor of exercise biochemistry at the University of Tsukuba and senior author of the studies told the
New York Times, “It is tempting to suggest that increased storage and utility of brain glycogen in the cortex and hippocampus might be involved in the development,” of a better, sharper brain.
“Although we can’t directly study brain glycogen metabolism in people,” said Dr. Robin Kucharczyk, chemistry professor at the University, “it would be interesting to conduct a study of MU students using the Fitness Center that would be analogous to the follow-up study done with the rats. Would the regularly exercising students perform better on a test of thinking and memory?”
Mike Minkin, senior health studies major, thought the study, “was really interesting. It makes sense that astrocytes increase in those who perform exercise on a daily basis. I know, personally, I feel more sharp and alert when I am in shape. I also feel as if I accomplish more as well. It is nice to see the science behind it. I would like to see a study on the measure of astrocytes and levels of motivation. It would be quite interesting to see if there is a correlation between the two.”
In summary, blood glucose levels fall during high intensity exercise due to energy consumption. This causes the brain to break down glycogen from astrocytes into glucose to fuel its metabolic functions. When the glycogen levels restore after rest, they actually rise higher than they were previously in regions of the brain involved in thinking and memory (among others), to new thresholds even. As you continue exercising, your brain glycogen levels in said areas theoretically can keep getting higher and higher, resulting in a heightened capacity to think critically and remember clearly.
So before the next batch of exams comes around, hit the gym before the books.
PHOTO COURTESY of commons.org
