If you've ever wondered how stressful it is to be president, Barack Obama's hair can give you a pretty good idea.
The presidency takes a pretty big toll.
"Stop calling me old. ... When I came into office, I had no gray hair. Now I have a lot. I don't dye my hair, and a lot of my fellow leaders do," President Obama said.
This video includes Getty Images and music by MADS / CC BY 3.0.