Running stimulates the brain in many positive ways. The best resource I’ve found is Spark, written by Dr. John Ratey. He and other neuroscientists have found that exercise turns on your brain in many positive ways.
Brain circuits are turned on for a better attitude, more vitality, and personal empowerment than any other activity.
Regular runs stimulate new brain cell growth at any age.
There is quicker problem-solving after a run.
Better decisions are made after a run.
Learning is enhanced after a run.
Running stimulates hormones that balance emotions.
The executive brain is turned on for better mental focus.
Energy is the top priority for the human organism. Our human brains developed over several million years to solve problems during the search for food. Starting a run in prehistoric times turned on the circuits to increase the chance of finding food. It is believed that when on a food-gathering mission, the memory circuits were turned on and increased to remember how to find the food, how to find routes to avoid predators, and, most important of all, how to find the way back.
Anthropologists believe that during the period 2 million to 1 million years ago humans were forced to expand their migration range to find food. This was also the period in which our ancestors started moving mostly on two feet (instead of four) and started traveling in groups. All of these challenges greatly expanded their brains.
During the long-distance treks, human traits of trust, cooperation, and mutual care developed.
Running was probably the first form of two-footed locomotion—but was not used often because valuable energy resources were consumed rapidly. Remember that the most common cause of death was starvation, and walking allowed humankind to cover great distance with minimal use of fuel.
But when our ancestors ran, it was usually because of a threat—escaping a predator or jumping over a snake. This stimulated all mind–body systems to work at top capacity.