source: http://www.prosebeforehos.com/anonymous_banker/08/31/don%E2%80%99t-sleep-so-much/
In hindsight, my high school Algebra teacher may have been certifiably insane. The first day of class he wandered off on a tangent about a Medieval prince who loved his sleep. This prince loved his sleep so much he decided to sleep five minutes longer every night: 8 hours, 8 hours 5 minutes, 8 hours 10 minutes … until he slept over 24 hours. Then, he died. Class dismissed, Professor continued. Don’t forget the quiz on polynomial expressions this Thursday.
I asked around, and no one has ever heard of this prince’s cautionary tale. I did, however, find a bizarre news story about 15-year old British girl named Louisa Ball. My friends sleep through half of every class (but still get better grades). And I’ve been known to sleep through flights. But Louisa sleeps through entire family vacations. Louisa is stricken with a rare disease called Kleine-Levin Syndrome, dubbed Sleeping Beauty Disease, that makes her sleep for weeks. Her longest snooze was 13 straight days. Baffled doctors can’t stop it, so Louisa’s parents must her wake up once a day so she can eat and use the bathroom.
In spite of Louisa’s affliction, people today sleep less than ever before. According to an American Cancer Society study, Americans slept 8 hours a night in 1960. Today? 6.7 hours. That’s a groggy 15% drop in sleep within 50 years—despite NBC’s late-night lineup’s best efforts. In our defense, our grandparents/parents didn’t have the following distractions: sensationalized 24-7 news-cycles, Red Bull, the Internet, and late-night SportsCenter reruns. National Geographic pegged the costs of our national “sleep debt” at $15 billion dollars in health care expenses and up to $50 billion in lost productivity (or Syria’s nominal GDP).
As usual, our grandparents were right. Eight is the correct answer for number of sleep hours. Sleep more than that and you are more likely to die sooner. A University of California San Diego psychiatry study found “sleeping more than 7 to 8 hours per day has been consistently associated with increased mortality.” But beware of sample bias here. The guy who sleeps 11 hours a night is more likely to be lazier and/or unhealthier.
Sleep less than 8 hours and you are more likely to be a) cranky and b) fat. Scientists observed a hormonal correlation between sleep deprivation and obesity. The hormone ghreline triggers your appetite and is found in higher concentrations in sleep-deprived people. Another hormone, leptin, lets your body know when it’s full and was seen in much lower levels in the under-slept.