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

Toward the end of his time in office, President Barack Obama joked about his graying hair.

“The first thing I want from young people is to stop calling me old,” Obama said in 2015. “When I came into office, I had no gray hair, and now I have a lot. I don’t dye my hair, and a lot of my fellow leaders do. I won’t say who, but their barbers know, their hairdressers.”

Indeed, despite his close-cut hairstyle, it was impossible not to notice the trademark presidential graying, as the president’s short black hair had become more of a salt-and-pepper color.

And though some dermatologists maintain that Obama was the latest victim of an expedited aging process in which presidents appear to age faster because of the stress of the office, others say that it’s more attributable to natural aging than stress.

Other studies, including a comprehensive analysis of elections dating back to the 1700s, have found that heading a nation can take years off a leader’s life. The analysis, from the Harvard Medical School, found that elected heads of government, on average, had lives almost three years shorter than those of the candidates they defeated.

Here’s how the country’s past presidents have looked near the beginnings and ends of their respective terms.

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

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

George W. Bush making a phone call shortly after the 2000 election.

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

Hillary Clinton whispering to Bill Clinton at a dinner several days before his first inauguration in 1993.

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

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

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

President Ronald Reagan and first lady Nancy Reagan greeting fans in Washington at his first inauguration, in January 1981.

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

Jimmy Carter emerging from a Georgia voting booth on Election Day in November 1976.

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

President Richard Nixon giving 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 proclaiming 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, with Nixon shortly after Nixon was elected president in November 1968.