While the graying of the president is a well-documented phenomenon, the conventional wisdom may be a bit off. As the Associated Press reported in 2011, a study of American presidents has shown that they often live longer than their cohorts. According to the AP's reporting:
"The graying of hair and wrinkling of the skin seen in presidents while they're in office are normal elements of human aging," said study author S. Jay Olshansky, a researcher on aging at the University of Illinois at Chicago.
Stress can speed up those two outward signs of aging, and it's possible that job stress has made some presidents appear to age quickly. But the study shows that doesn't mean being doomed to an early grave.
"We don't actually know if they get more gray hair or more wrinkles" than other men their age. "But even if they did, we don't die of gray hair and wrinkles," Olshansky said.
Presidents are generally well-taken-care-of people, which may account for their longevity. But there is scientific evidence to suggest that chronic stress can induce premature aging on the cellular level. One study showed women who underwent exteme mental stress to have DNA that was prematurely aged 10 years compared to non-stressed women.
This all being true, the proof is in the pictures, right? Scroll through the gallery below of Obama and his Cabinet from several years ago compared with now and judge for yourself.