It's no secret that our lives have become more sedentary than our stone age ancestors. Exercise improves brain health, inducing the development of new brain cells, but the link between exercise and our brain's extends far back in history. New research suggests that the link between exercise and the brain is a product of our evolutionary history and our past as hunter-gatherers, and the same parts of the brain that are taxed during complex tasks such as foraging also benefit from exercise. Researchers argue that as humans transitioned from a sedentary, apelike existence to a more physically demanding, hunter-gatherer lifestyle about 2 million years ago, we started carrying out foraging tasks, which may explain the connection between the brain and physical activity. Two University of Arizona researchers who run a research program on exercise and the brain have developed an'adaptive capacity model' for understanding, from an evolutionary neuroscience perspective, how physical activity impacts brain structure and function.