There is a half life people with injured spines exist within. I know. I am one of them. That life consists of never easing pain, medications, doctors, and a whole slew of people in your life who assume you are a "drug addict" because you're under a pain management doctor's care. Add to that a joint replacement and everything gets exponentially worse. Once you factor in the fact that replacement parts wear out, and you face a lifelong vista of surgeries from which you get only a minimum of relief.
I am almost exactly ten years older than Peyton and have been dealing with all of the above for 14 years. I have a broken prosthetic in my spine, a fusion around it, a knee replacement, neurological damage to both legs and the prospect of another couple pf surgeries within a couple of years. I would not wish this existence upon ANYONE whose guts I hated to the core, much less Peyton Manning.
Peyton knows his body and he is a brilliant man. I only hope to God that no one stupidly advises him to play another year. No one who is a Manning fan should want that for him either.
Leave the man alone. He's done enough.