I'm skeptical about those Widepedia life spans. It wouldn't surprise me if they included things like infant mortality, childhood disease deaths, and mothers in childbirth deaths in that average of 49. I'll have to Google to verify, though.
Remembering that the Constitution doesn't allow for the office of president to be held before age 35, think I'm remembering right.
I believe that life span includes infant mortality, which gives people the impression that everyone died around 40 until just a few years ago.