The evolutionary history of humans explains why physical activity is important for brain health

As explained by David A. Raichlen, director of the evolutionary exercise biology laboratory at the University of Southern California, and Gene E. Alexander, director of the brain imaging, behavior and aging laboratory at the University of Arizona, there were two key events to evolutionary level that link exercise with brain function.


Bipedism: going from walking on all fours to making it upright requires that our brains must coordinate a large amount of information and, in the process, make adjustments to muscle activity throughout the body to maintain our balance. In coordinating these actions, we must also be aware of any environmental obstacles. That is, unlike our quadruped ancestors, our brains began to be more cognitively challenged.

Hunting and gathering: the hominid way of life changed to incorporate higher levels of aerobic activity. Fossil evidence indicates that in the early stages of human evolution, our ancestors were probably relatively sedentary biped apes that ate mainly plants. However, about two million years ago, as habitats dried up in cold weather, at least one group of ancestral humans began to feed in a new way, hunting animals and collecting plant foods. Hunting and gathering involve much more aerobic activity than in other apes.

When looking for food away, hunter-gatherers should inspect their surroundings to make sure they know where they are. This type of space navigation is based on the hippocampus, the same region of the brain that benefits from exercise and tends to atrophy as we age. In addition, they have to scan the landscape for signs of food, using sensory information from their visual and auditory systems. They should remember where they have been before and when certain types of food were available.

All this is vital.