Skip to content

Sleep Disorders Health Center

Sleep Deprivation Leads to Trouble Fast

Losing Just 2 Hours of Nightly Sleep Hinders Thinking, Memory
Font Size
A
A
A
By
WebMD Health News

March 14, 2003 -- If you think you're getting enough sleep on fewer than six hours a night, you're probably experiencing the latest documented effect of sleep deprivation: the inability to realize just how tired you really are.

Even missing out on the recommend eight hours of nightly sleep for two weeks -- a fate regularly experienced by millions of Americans -- can accumulate to a "sleep debt" equal to total sleep deprivation of two full nights, finds a new study. Average only four hours a night in that time and your brain reacts as though you haven't slept at all for three consecutive nights.

"And the most worrisome part of this is these people don't realize how sleep-deprived they really are," lead researcher Hans P.A. Van Dongen, PhD, assistant professor of sleep and chronobiology at the University of Pennsylvania School of Medicine, tells WebMD. "When people are put through chronic sleep deprivation, there is an initial response where they say, 'OK, this is not optimal but I'll manage.' But after a few days of this, things are much worse than they realize."

In other words, they actually become too tired to realize just how tired they are. They may feel only a little tired, says Van Dongen, but they have slower reaction time, weakened memory, and other thinking impairments.

His study, published in the March 15 issue of Sleep, is the latest to document the growing list of health risks from sleep deprivation. Two months ago, Harvard researchers found that regularly getting too little sleep boosts heart disease risk, while previous research linked consistent sleep loss with a higher risk of diabetes and obesity. In a finding similar to Van Dongen's, Israeli researchers reported two weeks ago that children who got just one hour less sleep a night than their peers scored far worse on various memory and attention tests.

Van Dongen and colleagues evaluated the effect of mild and moderate nightly sleep loss on 48 young and middle-aged adults. After the sleep deprivation, scores on various types of thinking and memory tests were on par with those of people who were totally deprived of sleep for two consecutive nights. Like the Israeli finding, Van Dongen learned that missing just an hour or two on a regular basis can produce devastating results.

1 | 2 | 3

Today on WebMD

fatigued senior woman
We’ve got 10 tips to show you how
Man snoring in bed
Know your myths from your facts.
 
Young woman sleeping
What do your dreams say about you?
woman eith hangover
It’s common, and really misunderstood.
 

Is This Normal? Get the Facts Fast!

How Many Hours Did You Sleep Last Night?
Is that amount of sleep typical for you?
Did you get enough sleep to feel alert today and function at your best?

Get the latest Sleep Disorders newsletter delivered to your inbox!


or
Answer:
0-6
7-8
9+

Your level is currently

You say you are able to function well with fewer than seven hours of sleep. Some people say they can function on four to six hours of sleep each night, but research shows that adults who get fewer than seven hours of sleep — whether for just one night or over the course of days, weeks, or months — have more difficulty concentrating and more mood problems than people who sleep seven to nine hours.

Since you usually get too little sleep, please talk to your doctor about your sleep patterns. Poor quality sleep can affect many areas of your life and health, and your doctor may be able to help you if you have insomnia or other conditions affecting your sleep.

Sleep deprivation can have both short- and long-term consequences. Learn more about the health consequences of sleep loss. If you're concerned about having trouble falling asleep or staying asleep, assess your risk for a sleep disorder.

It's not surprising you feel that you're not functioning at your best today. Some people say they can function on four to six hours of sleep each night, but research shows that adults who get fewer than seven hours of sleep — whether for just one night or over the course of days, weeks, or months — have more difficulty concentrating and more mood problems than people who sleep seven to nine hours.

Since you usually get too little sleep, please talk to your doctor about your sleep patterns. Poor quality sleep can affect many areas of your life and health, and your doctor may be able to help you if you have difficulty sleeping, have insomnia, or have other sleep disorders.

Learn more about the health consequences of sleep loss. If you're concerned about having trouble falling asleep or staying asleep, assess your risk for a sleep disorder.

It's not surprising you feel that you're not functioning at your best today. Some people say they can function on four to six hours of sleep each night, but research shows that adults who get fewer than seven hours of sleep — whether for just one night or over the course of days, weeks, or months — have more difficulty concentrating and more mood problems than people who sleep seven to nine hours.

It's good that you usually do get more sleep, since sleep deprivation can have both short- and long-term consequences. Learn more about the health consequences of sleep loss. And if you're concerned about having trouble falling asleep or staying asleep, assess your risk for a sleep disorder.

You say you are able to function well with fewer than seven hours of sleep. Some people say they can function on four to six hours of sleep each night, but research shows that adults who get fewer than seven hours of sleep — whether for just one night or over the course of days, weeks, or months — have more difficulty concentrating and more mood problems than people who sleep seven to nine hours.

It's good that you usually do get more sleep because sleep deprivation can have both short- and long-term consequences. Learn more about the health consequences of sleep loss. And if you're concerned about having trouble falling asleep or staying asleep, assess your risk for a sleep disorder.

It's not surprising you feel that you're not functioning at your best today. Some people say they can function on four to six hours of sleep each night, but research shows that adults who get fewer than seven hours of sleep — whether for just one night or over the course of days, weeks, or months — have more difficulty concentrating and more mood problems than people who sleep seven to nine hours.

Since you usually get less sleep, please talk to your doctor about your sleep patterns. Poor quality sleep can affect many areas of your life and health, and your doctor may be able to help you if you have difficulty sleeping or have insomnia or other sleep disorders.

Learn more about the health consequences of sleep loss. If you're concerned about having trouble falling asleep or staying asleep, assess your risk for a sleep disorder.

It's wonderful that you got a good night's sleep last night. Many people struggle to do so. Having a good sleep routine often is the key to getting the quality sleep night after night that your body needs for optimal health. Whether your sleep routine involves taking a warm bath, reading a book, or meditating, it's important to keep your bedtime and routine consistent every night and wake up around the same time every morning.

Click here to read more about the importance of sleep. If you're concerned about having trouble falling asleep, staying asleep, or sleeping too much, assess your risk for a sleep disorder.

It's unfortunate you're not functioning at your best today. You say you had a good quantity of sleep last night, but maybe the quality of your sleep is not as good as it could be? Having a good sleep routine — including a consistent bedtime and wake time — often is the key to getting the quality sleep night after night that your body needs for optimal health. Since you usually sleep this amount, if you often aren't feeling your best, you should consider talking to your doctor. Could you have an underlying condition? Are you feeling anxious or depressed? Have you taken medication that disrupted your sleep? Do you or could you have sleep apnea? Or do you naturally require a little bit more sleep?

Although sleep is crucial for optimal health, some research suggests that sleeping too much can also have negative consequences. Learn more about sleep. If you're concerned about having trouble falling asleep, staying asleep, or sleeping too much, assess your risk for a sleep disorder.

It's unfortunate you're not functioning at your best today. You say you had a good quantity of sleep last night, but maybe the quality of your sleep is not as good as it could be? Having a good sleep routine — including a consistent bedtime and wake time — often is the key to getting the quality sleep night after night that your body needs for optimal health. Since you usually sleep longer, if you often aren't feeling your best, you should consider talking to your doctor. Could you have an underlying condition? Are you feeling anxious or depressed? Have you taken medication that disrupted your sleep? Do you or could you have sleep apnea? Or do you naturally require a little bit more sleep?

Although sleep is crucial for optimal health, some research suggests that sleeping too much can also have negative consequences. Learn more about sleep. If you're concerned about having trouble falling asleep, staying asleep, or sleeping too much, assess your risk for a sleep disorder.

It's wonderful that you got a good night's sleep last night. Many people struggle to do so. Having a good sleep routine often is the key to getting the quality sleep night after night that your body needs for optimal health. Whether your sleep routine involves taking a warm bath, reading a book, or meditating, it's also important to keep bedtime consistent and wake up around the same time every morning.

Although sleep is crucial for optimal health, some research suggests that sleeping too much can have negative consequences. Learn more about sleep. If you're concerned about having trouble falling asleep, staying asleep, or sleeping too much, assess your risk for a sleep disorder.

It's unfortunate you're not functioning at your best today. You say you had a good quantity of sleep last night, but maybe the quality of your sleep is not as good as it could be? Having a good sleep routine — including a consistent bedtime and waking up at the same time — often is the key to getting the quality sleep night after night that your body needs for optimal health.

Since you usually get less sleep, please talk to your doctor about your sleep patterns. Poor quality sleep can affect many areas of your life and health, and your doctor may be able to help you if you have insomnia, another sleep disorder, or conditions affecting your sleep.

Learn more about the health consequences of sleep loss. If you're concerned about having trouble falling asleep or staying asleep, assess your risk for a sleep disorder.

It's wonderful that you got a good night's sleep last night. Many people struggle to do so. Having a good sleep routine often is the key to getting the quality sleep night after night that your body needs for optimal health.

Since you usually get less sleep, talk to your doctor about your sleep patterns. Poor quality sleep can affect many areas of your life and health, and your doctor may be able to help you if you have insomnia or another sleep disorder or conditions affecting your sleep.

Learn more about the health consequences of sleep loss. If you're concerned about having trouble falling asleep or staying asleep, assess your risk for a sleep disorder.

SOURCES:

Centers for Disease Control and Prevention (CDC). Effect of short sleep duration on daily activities--United States, 2005-2008. MMWR Morb Mortal Wkly Rep 2011; 60:239.

Carskadon, MA, Dement, WC. Normal Human Sleep: An Overview. In: Principles and Practices of Sleep Medicine, Fifth, Kryger, MH, Roth, et al. (Eds), Elsevier Saunders, St. Louis, MO 2011. p.16.

Harvard University: "Sleep, Performance, and Public Safety."

Did You Know Lifestyle Choices
Impact Your Sleep?

Use the WebMD Sleep Tracker to track
your ZZZs over time.

Get Started

This tool is intended only for adults 18 and older.

Start Over

Step:  of 

Young woman sleeping
Quiz
Cannot sleep
Video
 
child sitting in bed
Article
Woman with insomnia
Quiz
 
nurse sleeping
ARTICLE
Foods That Help Or Harm Your Sleep
SLIDESHOW
 
Insomnia 20 Tips For Better Sleep
Slideshow
Pain at Night
ARTICLE