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How Long Can You Go Without Sleep?

Lara Vargas


According to the CDC, 35.2% of adults in the United States report consistently not getting enough sleep, but how much sleep do we really need? While the CDC recommends at least 7 hours of sleep for adults, children and teenagers need even more sleep. A pattern of getting less than the recommended minimum will lead to sleep deprivation.

After a restless night, the average person will struggle the next day. Everyday tasks, such as driving, become much harder, but most people recover after a full night’s sleep. One night of poor sleep may not seem like a big deal because of the fast recovery; however, a pattern of sleep deprivation can have serious health consequences.

What is Sleep Deprivation?

Sleep deprivation occurs when you’re getting less than the recommended amount of sleep each night. For adults, that’s 7 to 9 hours. Teenagers and children need even more sleep—the CDC recommends 8 to 9 hours for teens and 9 to 12 hours for school-age children.

Sometimes it isn’t possible to sleep for these recommended hours. While an occasional night of poor sleep shouldn’t drastically impact your health, a pattern of sleeplessness certainly will.

Usually, sleep deprivation comes from consistently missing a few hours of sleep each night. Most people don’t stay awake for a full 24 hours simply because they get too tired. Whether your sleeplessness comes from a pattern of short nights or one all-nighter, the causes of sleep deprivation remain similar.

Causes of Sleep Deprivation

Some causes of sleep deprivation include:

  • Sleep disorders such as insomnia, sleep apnea, and narcolepsy
  • Aging
  • Anxiety and depression
  • Changes in schedule
  • Newborns
  • Stress

Someone with insomnia has repeated difficulty falling asleep or staying asleep. Insomnia is more common in women and older adults, but anyone can suffer from it.

Sleep apnea occurs when the airway becomes blocked during sleep. Certain people are more likely to suffer from sleep apnea, including those with obesity, large tonsils, and heart or kidney failure. When you have sleep apnea, you’ll wake up gasping for air, and may have loud snoring—both of which cause fragmented sleep.

Narcolepsy is a disorder that affects your sleep/wake cycles and causes uneven sleep patterns. People with narcolepsy become excessively sleepy during the day and can even lose muscle control. Because of the excessive daytime sleepiness, people with narcolepsy often have trouble sleeping at night.

As you get older, you tend to experience more sleep problems. Older people often frequently wake during the night, causing fragmented and restless sleep. Additionally, sleep disorders such as insomnia worsen with age.

Sleep and mental health are interrelated. Individuals with anxiety and depression are more likely to struggle with insomnia and other sleep disorders. Specifically, about 65% to 90% of adults with depression and about 50% of adults with anxiety suffer from some kind of sleep disorder. Ironically, struggling with sleep makes you more likely to develop depression. Occasionally, sleep disorders can precede anxiety, but it’s far more common for sleep disorders to lead to depression.

Changes in schedule and newborns cause the same problem. If you suddenly start a new shift at work, it’s difficult for your circadian rhythm to adjust. Similarly, caring for a new baby demands a change in schedule. Though new babies need lots of sleep, they tend to be restless and require care during the night. Thus, parents of newborns tend to have fragmented sleep. Both a change in schedule and having a new baby shifts your sleeping routine and affects how soundly you rest.

Stress can cause sleepiness because the hormones it releases can cause wakefulness. These hormones are a part of the fight or flight response. Evolutionary, this effect of stress hormones makes sense. When our ancestors faced dangerous predators, it was useful to have hormones that kept them awake and alert. Today our stresses usually come from deadlines and other invisible causes; however, stress hormones can still prevent deep sleep.

With so many causes, sleep troubles can plague just about anybody.

Effects of Sleep Deprivation

With just one night without enough sleep, side effects set in right away. You may experience:

  • Fatigue and sleepiness
  • Reduced coordination
  • Increased appetite
  • Mood changes
  • Inability to concentrate
  • Lower motivation
  • Memory problems

Pulling an all-nighter may not be completely detrimental to your health, but each of these symptoms can make your day more difficult. Driving and working become nearly impossible when it’s difficult to concentrate. Moreover, a pattern of poor sleep causes serious health problems.

Consistently sleeping less than 7 hours per night can lead to a greater risk of:

  • Obesity
  • Diabetes
  • High blood pressure
  • Heart disease
  • Strokes
  • Anxiety and depression

What Happens When You Don’t Get Enough Sleep?

The negative effects begin after just 24 hours without sleep and worsen the longer you go without rest.

The longest someone has ever stayed awake is 264 hours, or about eleven consecutive days. In an effort to win his high school’s science fair,  Randy Gardner set out to break the Guinness world record for sleep deprivation. With the help of two friends, Gardner began his experiment with sleeplessness.

Two different researchers observed and monitored Gardner during this experiment. Sleep psychologist William Dement observed small behavioral changes; however, Lt. Cmdr. John J. Ross of the U.S. Navy Medical Neuropsychiatric Research found very different results. While Dement claimed Gardner merely suffered from moodiness and a heightened ability to smell, Ross reported serious cognitive difficulties. By day 4, Gardner was hallucinating and by day 6 Gardner struggled to speak clearly. On his final day without sleep, Gardner struggled to focus. Ross asked him to count backward by 7 from 100. Gardner could only get to 65 before forgetting what he was asked to do.

After he broke the previous world record of 260 hours, Gardner fell asleep for fourteen hours and seemingly recovered after re-establishing healthy sleep hygiene. However, in an interview, he says he later struggled with sleeping and blames his 11 days without sleep.

After 48 Hours

After 48 hours without sleep, it’ll be even harder to stay awake and concentrate.

In addition to struggling to concentrate, you may even experience microsleeps. During a microsleep, part of your brain shuts down for a few seconds. People often experience these local sleeps as zoning out. However, they can have dangerous side effects; these periods of microsleep are likely the reason people fall asleep while driving.

Even when microsleeps occur without incident, they are a sign of a deeper problem. Microsleeps signal the brain isn’t at full capacity. Whether or not your part of your brain is currently asleep, experiencing microsleeps suggests you’ll struggle with concentration and alertness.

Researchers at the Department of Psychiatry of the University of Wisconsin-Madison also discovered that microsleeps affect movement. They compared how neurons fired in fully awake and sleep-deprived rats. The rats that experienced microsleeps dropped a sugar pellet more frequently than the rested rats. This suggests that a brain experiencing microsleeps will make more mistakes and cannot function as well without proper rest.

Microsleeps in humans likely have a similar effect. Although microsleeps only last a few seconds, they affect overall performance. If you’re already experiencing microsleeps, then you cannot function at your full capacity. You’ll struggle to process information even when part of your brain isn’t locally asleep.

72 Hours Without Sleep

After 72 hours all the symptoms worsen. You will be unable to stay awake on your own and will likely be irritable. This irritability is evidenced in two astronauts who stayed awake for three days straight. Beyond being extremely tired and struggling with thinking, these astronauts experienced an increased heart rate, trouble processing information, and less positive emotions after remaining awake for so long.

Can Sleep Deprivation Kill?

It’s uncommon that people die as a direct cause of sleep deprivation. However, research shows a lack of sleep can kill. Allan Rechtschaffen—a doctor at the sleep research laboratory at the University of Chicago—kept ten rats awake for 11-32 days, until they died.

Although the rats were deprived of sleep for days, the researchers couldn’t identify a specific cause of death. All the rats suffered from lesions, weight loss, and a weakened appearance. Even though the specific cause of death remains unknown, it can be attributed to the side effects of severe sleep deprivation.

Another example comes from a soccer fan in 2014. He stayed awake for 48 hours as he tried to watch the entire World Cup, but died after suffering a stroke. Experts believe his death was linked with his sleep deprivation.

Additionally, sleep deprivation can cause accidents. Driving while drowsy is incredibly dangerous. According to the National Highway Traffic Safety Administration, drowsy driving caused an average of 83,000 crashes per year between 2005 and 2009. Of those crashes, an average of 886 was fatal each year.

In some rare cases, those with fatal familial insomnia (FFI) can die from chronic sleep deprivation. FFI is an inherited disease that affects the thalamus, the part of the brain that controls the sleep-wake cycle. FFI usually begins as mild insomnia in mid-life and quickly progresses into chronic sleep deprivation. Additional symptoms can include “weight loss, lack of appetite, too high or too low body temperature, and rapidly progressive dementia.” Death from this inherited disease usually occurs within 1 to 1½ years.

So yes, sleep deprivation can kill. Knowledge of the dangers of sleep research comes from anecdotal experience because researchers cannot directly experiment on how long it takes sleep deprivation to kill. However, the fact remains that a consistent lack of sleep is deadly.

Frequently Asked Questions

What happens if you sleep too much?

Sleep plays an important role in brain function, cell regeneration, and mood regulation. We need at least 7 to 8 hours a night to maintain proper physical and mental health. However, when we get more than 9 hours of sleep a night, we may start to see a decline in our cognitive performance and our ability to control emotions. If you sleep this long on a regular basis, it can lead to an increased risk of heart disease, stroke, and diabetes. Longer sleep times are typically a result of poor sleep the night before or over several days.

Why can’t I sleep even though I’m tired?

If you are tired but can’t get to sleep, it is likely due to a high level of cortisol (the stress hormone). When we are plagued with worries, we often experience racing thoughts before bed. This anxiety can cause cortisol to flood your system, keeping the mind active, and making it impossible to sleep. To prevent this, you can perform relaxing activities before bed, such as taking a warm bath or shower, reading, writing in a journal, or practicing breathing exercises that calm the nervous system.

What is poor sleep hygiene?

Sleep hygiene involves activities that impact our ability to get a good night’s sleep. Good sleep hygiene includes tasks such as keeping a set sleep schedule, avoiding caffeine after 3 pm, and performing relaxing activities before bed. All of these steps set you up for proper sleep. Poor sleep hygiene includes activities that have a negative impact on our sleep, such as keeping an erratic sleep schedule, intentionally putting off sleep, and eating heavy meals before bed.

Is it good to sleep with your phone next to you?

We do not recommend sleeping with your phone next to you. The blue light from an electronic screen can mimic sunlight and causes the brain to slow melatonin production (the sleep hormone). A lack of melatonin can also cause fewer and shorter REM cycles, causing you to feel unresting even if you slept a full 7 to 8 hours.

Does oversleeping make you depressed?

Studies show that both long (more than 9 hours) and short (less than 7 hours) periods of sleep can cause mood disturbances that contribute to depression.  However, insomnia or a lack of sleep is more closely related to depression and poor mental health than longer sleep. In many cases, an eradicate sleep schedule can cause inconsistent sleep times and hormonal imbalances that also contribute to poor mood regulation.

How Long Can We Really Last Without Sleep?

It’s not truly known just how long people can remain awake without severe side effects or death. As previously mentioned, a man watching the World Cup for 48 hours straight died after suffering a stroke. But experts believe the stroke was caused by his extended sleep deprivation.

On the other hand, a high school student managed to stay awake for a 264-hour stretch, breaking the world record. While scientists can’t run an experiment to discover how long we can go without sleep, they all agree that sleep is essential. An occasional all-nighter likely won’t cause a stroke, but consistent poor sleep hygiene will impact your health.

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