Before-and-after photos show how dramatically presidents have aged while in office

Obama takes the oath of office on Inauguration Day, January 20, 2009.

The president wraps up a National Security Council meeting in December 2015.

Former President George W. Bush makes a phone call shortly after the 2000 election.

Bush fields questions during his final White House press briefing on January 12, 2009.

Hillary Clinton whispers to then-President-elect Bill Clinton at a dinner several days before his first inauguration in 1993.

Clinton gives a brief speech toward the end of his term in October 2000.

Appearing without his trademark glasses, then-Vice President George H. W. Bush answers a question at the second presidential debate in October 1988.

Bush addresses a crowd of veterans during a ceremony at the Korean War Memorial in June 1992, several months before losing re-election.

Former President Ronald Reagan and First Lady Nancy Reagan greet fans lined up in Washington at his first inauguration in January 1981.

Reagan returns to Washington after his final trip as president to Camp David in January 1989.

Jimmy Carter emerges from a Georgia voting booth on election day in November 1976.

An Associated Press photographer captures Carter preparing for his farewell address to the nation in January 1981.

President Richard Nixon gives a press conference in the East Room of the White House several weeks after being sworn in in 1969.

In this photo, a glassy-eyed Nixon delivers a final speech for White House staff and members of his cabinet.

President Lyndon Johnson proclaims a day of mourning for deceased President John F. Kennedy shortly after being sworn in.

Johnson, who didn't visibly age too much in his five-year tenure, joins Nixon shortly after Nixon is elected president in November 1968.