Life
How the brain is fueled by exercise
Young Woman exercising. PHOTO/Steve Prezant/Corbis
Moving the body demands a lot from the brain. Exercise activates countless neurons, which generate, receive and interpret repeated, rapid-fire messages from the nervous system, coordinating muscle contractions, vision, balance, organ function and all of the complex interactions of bodily systems that allow you to take one step, then another.
This increase in brain activity naturally increases the brain’s need for nutrients, but until recently, scientists hadn’t fully understood how neurons fuel themselves during exercise. Now a series of animal studies from Japan suggest that the exercising brain has unique methods of keeping itself fueled. What’s more, the finely honed energy balance that occurs in the brain appears to have implications not only for how well the brain functions during exercise, but also for how well our thinking and memory work the rest of the time.
For many years, scientists had believed that the brain, which is a very hungry organ, subsisted only on glucose, or blood sugar, which it absorbed from the passing bloodstream. But about 10 years ago, some neuroscientists found that specialized cells in the brain, known as astrocytes, that act as support cells for neurons actually contained small stores of glycogen, or stored carbohydrates. And glycogen, as it turns out, is critical for the health of cells throughout the brain.
