Human brain size has increased remarkably over the millennia. Perhaps it has outgrown itself to the point of being so large that injury is more likely. Although it has been reported that human predecessors had larger brains, their skulls were thicker, and better protected their brains against the rigors of their robust lifestyle.
Human brains are not adequately protected by the comparatively thinner skulls in existence today.
Some sports activities should be curtailed as a result. Football, boxing, and some other overly rigorous activities should be eliminated. These activities jar the brain excessively leading to bleeding and possible lesions in the brain. Some sports are less abusive to the brain and can continue despite the possibility, though less likely, of brain injury.
Exercise is a necessity so that the body will be healthy enough to support the very demanding needs of the brain. Good nutrition is also a necessity as the brain and body both require adequate vitamins and minerals. A good sound structure can not be built with junk parts.