There's a saying that presidents age twice as fast while in office. If that's true, be sure to wish President Barack Obama a happy 54th birthday on Tuesday and then see how he and other presidents have aged while in office.
Now, we move on to Clinton's predecessor, President George H.W. Bush, seen here taking the oath of office during inaugural ceremonies at the United States Capitol on Jan. 20, 1989. Bush was 64 years old in this photo.