SACRAMENTO, Calif. — People who exercise have better mental fitness, and a new imaging study from UC Davis Health System shows why. Intense exercise increases levels of two common neurotransmitters — glutamate and gamma-aminobutyric acid, or GABA — that are responsible for chemical messaging within the brain.
Published in the The Journal of Neuroscience, the finding offers new insights into brain metabolism and why exercise could become an important part of treating depression and other neuropsychiatric disorders linked with deficiencies in neurotransmitters, which drive communications between the brain cells that regulate physical and emotional health.
“Major depressive disorder is often characterized by depleted glutamate and GABA, which return to normal when mental health is restored,” said study lead author Richard Maddock, professor in the Department of Psychiatry and Behavioral Sciences. “Our study shows that exercise activates the metabolic pathway that replenishes these neurotransmitters.”
The striking change in how the brain uses fuel during exercise has largely been overlooked in brain health research. While the new findings account for a small part of the brain’s energy consumption during exercise, they are an important step toward understanding the complexity of brain metabolism. The research also hints at the negative impact sedentary lifestyles might have on brain function, along with the role the brain might play in athletic endurance.
To understand how exercise affects the brain, the team studied 38 healthy volunteers. Participants exercised on a stationary bicycle, reaching around 85 percent of their predicted maximum heart rate. To measure glutamate and GABA, the researchers conducted a series of imaging studies using a powerful 3-tesla MRI to detect nuclear magnetic resonance spectra, which can identify several compounds based on the magnetic behavior of hydrogen atoms in molecules.
Richard Maddock and his team conducted MRI exams of people before and after cycling on a stationary bicycle to determine the effect of exercise on neurotransmitters.
These findings point to the possibility that exercise could be used as an alternative therapy for depression. This could be especially important for patients under age 25, who sometimes have more side effects from selective serotonin reuptake inhibitors (SSRIs), anti-depressant medications that adjust neurotransmitter levels.
A copy of the study “Acute Modulation of Cortical Glutamate and GABA Content by Physical Activity” is available through Coleen Herbert, Society for Neuroscience, by calling 202-962-4000