The average human being of the 21st century has a problem: if he does
nothing he becomes sedentary. And it is so easy to become
sedentary! And so comfortable! Just do nothing.
Why does this happen? Simply because we are a relatively young species
whose technology has advanced much faster than its physical body. And it
was that four days ago we lived in the caverns ... If we didn't run we wouldn't
hunt and we didn't...