I wish the title to this article were hyperbole. But we now actually know of a mechanism within the brain whereby heavy squats and deadlifts fend off neural degeneration. This is not an overstatement. Feeling dumber as you age? Try intense exercise.
When we stop doing intense lower body movement (i.e. - sprinting, jumping, bounding, heavy weight training), we have a reduction in brain function and neuron growth.
The resultant degeneration in turn reduces our motor skill, further reinforcing lack of intense lower body movement, which of course amplifies the neural degeneration. And so on. It's a terrible catch-22 for which there's a pretty straightforward remedy: lift heavy, even when it hurts, sucks, doesn't seem to be making you skinny, or seems futile.