david kennerly / getty images

Jimmy Carter, Ronald Reagan, George H. W. Bush, Bill Clinton, George W. Bush and Barack Obama. Six men with distinctly different political views, but also with one thing in common: Each aged dramatically during his years in the Oval Office.

If you don't think being President of the United States is a high pressure job, just look at these 'before and after' photos of our last six Chief Executives. To see how Presidents, from Carter to Obama, age in office, JUST CLICK HERE!