Okay, not directly true as “How Exercise Fuels the Brain” points out. What is true, however, is that regular exercise increases the amount of glycogen the brain stores — and then the amount of fuel it has readily available to it for later.
While a brain with more fuel reserves is potentially a brain that can sustain and direct movement longer, it also “may be a key mechanism underlying exercise-enhanced cognitive function,” says Hideaki Soya, a professor of exercise biochemistry at the University of Tsukuba and senior author of the studies, since supercompensation occurs most strikingly in the parts of the brain that allow us better to think and to remember. As a result, Dr. Soya says, “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.
It’s not like I was going to stop exercising anytime soon anyway, but a benefit like improved brain function (which IN MY HEAD I translate to “makes me smarter”) can’t hurt.