31 miles is certainly possible, but I wouldn't want to do it on a daily basis even if I were in good enough shape to. While I enjoy riding, that's 4-6 hours a day down the tubes in terms of having a choice about what you do with your time.

If you do want to do it, you'll very probably have to build up to it. Maybe not if you've been keeping yourself in tip-top shape while off the bike, but I doubt that's the case.