Is it our imagination, or does every U.S. presidentís hair go gray in office? Experts say weíre not imagining things. And you can confirm it by looking at before-and-after presidential pictures. Bill Clinton got very gray after 4 years in office, so did George W. Bush. And Barack Obamaís hair is definitely getting lighter as we speak. 

Whatís the deal here? Is it from the high-stress of dealing with terrorists, budget cuts, and running for reelection, or is something else at work? Scientists say there are actually two factors involved in the graying of the presidents. First, human hair follicles can only grow so many normal-colored strands over a lifetime, and by the time we hit 30, the cells that create hair color start to die off, so, our hair starts to turn gray, one strand at a time. Also, most presidents take the oath of office in their 40s or 50s, and since thatís when their hair is graying the fastest, they often seem to go gray overnight.

But thatís not the only reason. Experts say that stress plays a big factor, too. When weíre stressed, our bodies pump out tons of adrenaline, cortisol, and free radicals - chemical combo that can cause our hair-color cells to die out prematurely, leading to early-onset gray hair. And since the presidency is by definition a stressful job, our commander-in-chiefs go gray more quickly than the average middle-aged man.