Exercising for 30 minutes a day will not only strengthen your heart and muscles, but also strengthen your brain.

Work up a sweat for just a half an hour and you will be able to learn faster, remember more, think more clearly and recover more quickly from brain injuries, such as a stroke.

How? LiveScience.com reports that exercise creates stress for the body--only in this case, that's a good thing. When you break into a jog, this aerobic exercise burns calories quickly, which becomes a threat to your energy reserves. Your body is screaming, "Danger!" That means all resources go to the brain to protect it.

The brain's neurons are quite vulnerable to disruptions in the energy supply. "If deprived of energy for more than one minute, the neuron dies," Fernando Gomez-Pinilla of UCLA told LiveScience.com. "All the physiology of the body is designed to protect the brain."

So the mild stress of exercise actually stimulates protective benefits that allow the release of brain-building growth factors, according to Carl Cotman, director of the Institute for Brain Aging and Dementia at the University of California in Irvine.

Exercise also improves brain function and the ability to learn as it makes the neurons stronger and healthier. Not only are new neurons formed, but also old ones grow and form better connections with one another. Blood vessels grow next to the neurons, giving glucose and other nutrients. As Cotman told LiveScience.com, exercise "builds the pipes" for improved cognition.