The connection between exercise and brain health has now been super conclusively and astonishingly shown, but what are some possible evolutionary reasons for this connection?
Maybe the extra energetic investment in brain health is only justified when there is an energetic surplus, and doing exercise correlates with having extra energy available? (As opposed to starving and thus needing to conserve energy.) But that doesn't actually make sense, since the extra metabolic expenditure of these processes can't possibly be all that high, and doesn't the brain use almost the same (huge) amount of resources whether it's at rest or very cognitively active?
Maybe the extra energetic investment in brain health is only justified when there is an energetic surplus, and doing exercise correlates with having extra energy available? (As opposed to starving and thus needing to conserve energy.) But that doesn't actually make sense, since the extra metabolic expenditure of these processes can't possibly be all that high, and doesn't the brain use almost the same (huge) amount of resources whether it's at rest or very cognitively active?