Sleepless Nation

An estimated 70 million Americans suffer from sleep disorders, ranging from common insomnia to the truly unusual—sleepwalking, night terrors, sleepeating and even sleepsex. In some rare cases, people have been observed smoking cigarettes…and even getting in their cars and driving for miles while asleep.

"Sleep is one of those spiritual processes," Dr. Oz says. "We let our base instincts shine through." Normally those instincts only show up in our brains while we dream—not during the dreamless "deep sleep" when the brain should be restoring itself. Dr. Oz says the reason some people sleepwalk is because the part of their brains that inhibits their movement lets its guard down and allows unconscious desires to slip through.

"When you dream, normally you're paralyzed, you can't move around," Dr. Oz says. "But when you're in a deep restorative sleep, you're not paralyzed. So your brain—some part of it—slips out. Your legs start moving, [but] your brain doesn't know where you are. That cortex that gives you judgment and executive function isn't there."