There's a saying that presidents age twice as fast while in office. With Thursday marking President Barack Obama's 55th birthday, take a look back over the past 60 years of U.S. presidents and judge for yourself how much the office aged them.
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.