Lifetime intellectual enrichment might delay the onset of cognitive impairment and be used as a successful preventative intervention to reduce the impending dementia epidemic… ~ PSMag
I fail to see how this is surprising.
When you go into space your muscles atrophy because there is no gravity. And when you come back to earth you have trouble walking.
Well, the brain is a muscle too, and most people live in space permanently. Punching a clock at a mindless job followed by binging on TV shows is what most people call living, so when they hit 50 their brains go mushy.
The body needs exercise. The fact that this applies to the brain just like everything else should be obvious.