There is a great line in Thirteen Days which dealt with JFK's handling of the Cuban Missile Crisis. Kevin Costner's character, who is special counsel to JFK, was talking to another charcter (possibly RFK) about the same issue. In essence he said, "I always look at that picture of Lincoln upstairs and how old he looked at the end. When we got here, I said 'That's not gonna happen to us.'"

While Bush will never be accused of being a hard worker, his approach has helped his appearance. He has definitely aged, but not significantly. I guess that's a benefit of spending nearly 1/3 of his presidency on vacation.