> I cannot keep from thinking that our brain and our legs are connected neurologically. They tap on the same space exploration abstractions.
Absolutely. Something happens during a bike marathon where my body and brain are eventually independent of my thoughts and I'm moving on autopilot with mild tunnel vision while thinking about complex thoughts, old memories, things I could have handled better. I can only attribute it to persistent eustress and the post-metabolic state of endorphin saturation combined with adrenaline.