Did you mean to ask "how old are you that you can't do [something you've never done before in your life and thus don't have the muscles for it] for five minutes what an 80 year old [who has done it every day of their life and thus has the required muscles] can do several times a day"?

Also, I'd like to point out the differences in length of time between taking a shit and a normal 8 hour work day.

I'm not saying this is impossible, but I understand the trepidation.