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More on Lost Sleep, More Risk
Lost Sleep, More Risk
New York (Jan 4, 2012)
Have you ever felt the irresistible undertow of sleep during a meeting, while driving, having a meal, or during that mid-afternoon lull at work? If daytime sleepiness is a problem you struggle with regularly you are probably among the estimated 20 percent of Americans who don't get enough sleep.
"There's no question that we're more sleep deprived than ever," said Carl W. Bazil, M.D., Ph.D., Director of the Comprehensive Epilepsy Center and Sleep Disorders Center at NewYork-Presbyterian/Columbia University Medical Center. "In American society it's considered lazy and is frowned upon to nap. Physicians, lawyers, and other professionals are trained to believe that sleep is a weakness, and they pride themselves on working very long hours with little sleep. But there's growing evidence that lack of sleep impairs people's performance."
A recent survey by the C.D.C. and the National Center on Sleep Disorders Research suggests the problem is widespread. More than 35.3% of 74,571 American adults surveyed about their sleep behaviors reported getting less than 7 hours of sleep during a typical 24-hour period, and 37.9% reported unintentionally falling asleep during the day at least once in the preceding month.
In the survey, 4.7% of respondents reported nodding off or falling asleep while driving at least once in the preceding month. And the National Department of Transportation estimates drowsy driving to be responsible for 1,550 fatalities and 40,000 nonfatal injuries annually in the U.S.
"This is a huge public health problem," said Dr. Bazil, but one that is challenging to address. There is no breathalyzer for sleepiness, for example. If an accident does occur it's hard to prove or disprove that a sleepy driver caused it. Additionally, unlike drunk driving, there are few campaigns against driving while tired, and limited stigma associated with driving while sleepy. Most accidents caused by sleepy drivers are probably thought to be random events rather than accidents that could have been prevented.
Another concern with driving is the recently identified but controversial symptom of sleep deprivation known as microsleep. Microsleep is a very brief change in the brain waves that lasts less than three seconds. Because the shift in consciousness is so brief, the sleeper may not even be aware that he or she has drifted into sleep.
"I believe microsleep is quite prevalent, particularly among people who are either sleep deprived or suffer from a sleep disorder that causes sleep fragmentation at night such as sleep apnea, periodic limb movement, or seizure disorders," said Ana C. Krieger, M.D., Director of the Center for Sleep Medicine at NewYork-Presbyterian/Weill Cornell Medical Center. But studying microsleep and its implications is no easy task. "As we don't routinely monitor brain activity on people during wakefulness, it is difficult to determine how often this occurs in the population."
To address sleepiness, doctors first need to determine what is preventing a good night's sleep. "The first question I ask people is, 'what is your nighttime sleep like?' Most can get by with less than eight hours of sleep a night for a few days, but there is a cumulative effect over time, and over seven to 10 days with less sleep, people will accumulate a sleep debt and their performance will deteriorate. I also ask about other sleep habits. Do you wake up at night, snore, kick, sleep walk, do you wake rested or tired? I go through a list of questions looking for causes," said Dr. Bazil.
If patients' problems appear to be due to sleep deprivation rather than a disorder, Dr. Bazil advises them to get more sleep, and talks to them about sleep hygiene and relaxation techniques. Changing their habits "takes some work on their part," he said. If, on the other hand, they have signs of a sleep disorder such as sleep apnea or restless leg syndrome they may need sleep testing, he added.
While the mystery of sleep is very slowly unraveling there's still much more to learn about sleep, Dr. Krieger said. "Whoever identifies all the processes of sleep will be quite renowned because it is a very, very complex mechanism that involves different parts of the brain, different receptors, an intricate communication system that we don't yet understand in detail."
Contributing faculty for this article:
Ana C. Krieger, M.D. is the Medical Director of the Center for Sleep Medicine at NewYork-Presbyterian/Weill Cornell Medical Center and an Assistant Professor of Medicine at Weill Cornell Medical College.
Carl W. Bazil, M.D., Ph.D. is the Director of the Comprehensive Epilepsy Center and Sleep Disorders Center at NewYork-Presbyterian/Columbia University Medical Center and the Caitlin Tynan Doyle Professor of Clinical Neurology at Columbia University College of Physicians and Surgeons.