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How long can a human go without sleep?

We can help you avoid this fate…

We can help you avoid this fate…

How long can a human go without sleep?

Tristan Hoag

By Tristan Hoag on May 17, 2018

Sleep deprivation can be frustrating, but how long can a human go without sleep?

Let’s just be honest. The reason you’re wondering how long can a human go without sleep is because it’s the middle of the night and you’re wide awake.


Get settled in, turn off the lights, and get ready to read an article so boring it’s almost guaranteed to put you straight to sleep…

Reading about sleep case studies should do the trick

No human has ever died from loss of sleep, only by coincidental situations such as a car accident caused by being overtired and falling asleep at the wheel.

What this means for your question, tired reader, is that there isn’t a simple answer.

In 1965, a high-school student stayed awake for 264 hours ‒ 11 days ‒ as part of a science fair project. This stands as the record for the longest run without sleep. Other experiments have managed to reach the eight to 10-day range. While these studies have resulted in useful information about the impacts of sleep deprivation, this record could be broken as soon as 12 days from now.

So, a simplistic answer is 11 days, unless you’re about to break that record yourself!

And these are studies of arguably normal people staying awake by force of will. If you start to look at medical conditions that involve sleeplessness, things get… strange.

Take Morvan’s syndrome for example, where the sufferer can go for several months with little to no sleep, and is subject to hallucinations, weight loss, muscle spasms and general pain.

Or Morvan’s big brother, Fatal Familial Insomnia. This is a prion disease, similar to mad cow disease, that treats its victims to brain degeneration, overactive nervous system, fever, weight loss and hypertension. After several months, sometimes years without sleep, the victim dies of multiple organ failure.

But, wait! I’m supposed to be helping you fall asleep! These are very rare diseases, and certainly aren’t anything for you to lose sleep over!

Impacts of lack of sleep

But maybe your question isn’t as much can you live without sleep as it is what living without sleep looks like. There are definite stages of sleep deprivation, and as you go longer without sleep, the symptoms increase in severity.

  • After 24 hours without sleep: Coordination, memory and judgement are impaired to a degree comparable with a blood alcohol content of 0.10.
  • After 36 hours without sleep: Your body starts to suffer, as inflammation markers spike in the bloodstream, hormones fluctuate and emotions begin to get extreme. Over long periods of time, this level of sleep deprivation can increase your blood pressure and your risk for heart disease
  • After 48 hours without sleep: At this point, the body begins to shut down involuntarily for a few seconds or minutes. These are called microsleeps, and the subject is completely unaware that they are happening.  Cognitive function unravels, and focus becomes impossible at time.
  • After 72 hours without sleep: From this point on, the subject suffers from increasingly severe cognitive deficits, and is prone to hallucinations. These will continue to increase until the body simply can’t continue without sleep.

In individual studies of sleep deprivation, the subjects were able to return to normal cognitive functioning after catching up on their rest. Individual instances of extended lack of sleep aren’t immediately dangerous. Over time, chronic lack of sleep will impact your overall health, though, increasing the risk of obesity, heart disease and type 2 diabetes.

You should consider visiting a sleep specialist if you regularly lose sleep, or if you experience some of the following symptoms:

  • Regularly feeling tired during the day
  • Breathing problems during sleep
  • Restlessness and involuntary jerking movement at night
  • Difficulty staying awake during inactive moments
  • Falling asleep while driving
  • Using coffee or energy drinks to get through your day
  • Regularly using sleep aids at night

These are the signs of the dangerous side of sleep deprivation; not the frustrating and panic-spawning sleepless nights, but the slow burn of operating for extended periods without enough sleep.

Quick – how many sheep do you see?
Quick – how many sheep do you see?

Maintaining a normal sleep pattern

You’re still awake? Impressive…

If it’s so bad not to get enough sleep, what constitutes enough sleep? The standard answer is seven to nine hours per night. It’s healthier to sleep for a consistent amount each night, rather than sleeping too little and catching up in bursts.

While this is the general guideline, individuals can vary greatly in the amount of sleep they need. If you require less sleep, and are happy and healthy, stick with what works for you!

Combatting insomnia

If you find yourself regularly going without sleep, there are steps you can take to improve your odds of a good night’s sleep. The goal is to find the right sleep environment, and the right routine to relax at night. Getting yourself set up in advance can help you have a more relaxing night.

Some things you can try include:

  • Keeping your bedroom cool, dark and quiet
  • Masking out background sounds with a white noise machine or earplugs
  • Going to bed and waking on a consistent schedule
  • Turning off electronics an hour before bedtime

To improve the quality of your sleep, you should avoid:

  • Engaging in stressful activities in the evening
  • Taking naps, even if you feel tired during the day
  • Drinking anything during the hour before bed
  • Drinking alcohol before bedtime
  • Drinking caffeine six hours before bedtime
  • Eating heavy meals late in the evening

It can also help to keep a sleep diary, tracking when you went to sleep, when you woke, what you ate, and any other details that you consider relevant. This can help you to identify patterns and find things that are making it harder for you to get your rest.

If you’re still awake and reading this, then, regretfully,  I have failed you, dear reader. If the elusive specter of sleep still escapes you, and you have serious concerns about your ability to get enough sleep, the Experts on JustAnswer are available at any time to answer health questions such as “How long can a human go without sleep?”

You can’t sleep, so our Experts won’t either.

Share your stories of sleep deprivation and woe in the comments! Seriously, what else are you going to do at this hour?