Physical exercise is good for your brain. And I mean really good for it. The brain burns a ton of energy during exercise, much more, even, than if you were thinking really hard about something really complicated. New research has discovered just what the brain does with all that extra energy.
"From a metabolic standpoint, vigorous exercise is the most demanding activity the brain encounters, much more intense than calculus or chess, but nobody knows what happens with all that energy," says the paper’s lead author Richard Maddock, of UC Davis.
One thing the brain is doing is building more neurotransmitters. In fact, it gets so busy doing this that brain fatigue might be the cause for endurance athletes hitting "the wall," and not physical exhaustion. "We often think of this point in terms of muscles being depleted of oxygen and energy molecules. But part of it may be that the brain has reached its limit," Maddock told the UC Davis Newsroom.
The study hooked up volunteers to sensors and an MRI while they exercised (a control group was measured without exercising), and found that certain parts of the brain lit up, notably the visual cortex, along with the "anterior cingulate cortex, which helps regulate heart rate, some cognitive functions, and emotion." Could it be that when we’re physically exerted, the brain also preps itself for action?
The tests also found that the brain increased its levels of glutamate and GABA (gamma-aminobutyric acid), a neurotransmitter. Regular exercise raises the base level of glutamate, which is responsible for synthesizing GABA, and is itself a neurotransmitter, carrying signals around the brain. "There was a correlation between the resting levels of glutamate in the brain and how much people exercised during the preceding week," says Maddock.
This increase in brain health may let exercise take the place of antidepressants in some cases. One example cited by UC Davis’s Karen Finney is that people who experience side effects from SSRI antidepressant drugs might benefit. SSRIs alter the levels of neurotransmitters in the brain, which would seem to have a clear link to this new research.
"Not every depressed person who exercises will improve," Maddock told Finney, "but many will. It’s possible that we can help identify the patients who would most benefit from an exercise prescription."
Yes, you read that right. Your doctor may prescribe you exercise.