I used to belong to a Science Book Club and ordered a book on snakes for a friend, so she could give it to her son on his birthday.
I read it before giving it to her.
According to the book, snakes have a Comfort Zone.
Get them too hot, they'll try to cool down. Get them too cool and they'll sunbathe—or something.
Now here is the thing:
Take a snake and keep him in his Comfort Zone continually—never too hot, and never too cool...
And according to the book, he'll die after about six months.
Apparently, being in less than ideal circumstances Occasionally at least, is necessary to their continued well-being.
I will never be in danger of dying due to too little aggravation.
I doubt that anything as simple and purely linear happens to people...
But I bet your Dude in the locked room would not be healthy after awhile...
Regardless of how healthy he ate, or how consistently he exercised.