"Let's do some sleep math. You lost two hours of sleep every night last week because of a big project due on Friday. On Saturday and Sunday, you slept in, getting four extra hours. Come Monday morning, you were feeling so bright-eyed, you only had one cup of coffee, instead of your usual two. But don't be duped by your apparent vim and vigor: You're still carrying around a heavy load of sleepiness, or what experts call "sleep debt"--in this case something like six hours, almost a full nights' sleep.
Sleep debt is the difference between the amount of sleep you should be getting and the amount you actually get. It's a deficit that grows every time we skim some extra minutes off our nightly slumber. "People accumulate sleep debt surreptitiously," says psychiatrist William C. Dement, founder of the Stanford University Sleep Clinic. Studies show that such short-term sleep deprivation leads to a foggy brain, worsened vision, impaired driving, and trouble remembering. Long-term effects include obesity, insulin resistance, and heart disease. And most Americans suffer from chronic deprivation.
A 2005 survey by the National Sleep Foundation reports that, on average, Americans sleep 6.9 hours per night--6.8 hours during the week and 7.4 hours on the weekends. Generally, experts recommend eight hours of sleep per night, although some people may require only six hours of sleep while others need ten. That means on average, we're losing one hour of sleep each night--more than two full weeks of slumber every year.
The good news is that, like all debt, with some work, sleep debt can be repaid"
Link to full article
Link to full article

