How Long Can We Physically Survive Without Sleep?


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Sleep is something we ALL need, and something we’ve all complained about not getting enough of. We struggle the day after pulling an all nighter, but how long can we physically survive without sleep?

No one actually knows.

What we do know is that the longest time anyone has ever stayed awake for is 11 days, 264 hours to be precise, a record set by Randy Gardner, who was a high school student when he attempted it.

Remarkably, Gardner didn’t show signs of negative health effects after achieving this incredible feat. His focus and mood were impaired, but after sleeping for 14 hours he seemed to be well recovered.

But surely there are risks involved with this level of sleep deprivation?

If you need to study through the night or skip sleep in order to meet a deadline, rest assured.

After reading the detailed information in this article, you will be knowledgeable on the subject of how long we can physically survive with sleep.

In this post I will cover:

  • How much sleep should we be getting?
  • Why do we need to sleep? And why so much?
  • What happens when we go without sleep?
  • Is it possible to force yourself to stay awake?
  • Fatal familial insomnia

Let’s get started!

How much sleep SHOULD we be getting?

The amount of sleep a human being requires differs from person to person. Age is a hugely important factor, along with how active a person is and their lifestyle choices such as diet and hydration.

On average, a healthy adult needs between 7 and 9 hours of sleep every night in order to function at their optimal level.

Due to the hurried nature of today’s world, many people feel that if they get six hours of sleep that is enough. Recent studies have show that even getting one hour less than the recommended amount can cause sleep deprivation.

It is often the case that people who get too little sleep don’t realise the benefits they would experience by turning off the TV an hour earlier and getting extra shuteye. 

Obviously, there’s no set rule for everyone. Genetics play a part, as does the energy a person expends in their daily endeavours.

Let’s take a look at the average time a person should ideally sleep based on their age group.

  • Newborn to 3 months – 14 to 17 hours
  • 4 to 11 months – 12 to 15 hours
  • 1 to 2 years – 11 to 14 hours
  • 3 to 5 years – 10 to 13 hours
  • 6 to 12 years – 9 to 11 hours
  • 14 to 17 years – 8 to 10 hours
  • 18 to 25 years – 7 to 9 hours
  • 26 to 64 years – 7 to 9 hours
  • 65+ years – 7 to 8 hours

As you can see from these averages, the amount of sleep we need decreases the older we get. This is due to our bodies needing more rest time in its formative years to cope with the intense growth and development, physically and cognitively.

As we get older, we need slightly less sleep because our body only needs to recover from the energy expended that day. Our growth period is complete and sleep is more for maintenance and recuperation. 

How long can we go without sleep

Why do we need to sleep? And why SO much?

We need sleep to process our thoughts, to go over what’s happened in the day and sort memories like a computer would into files. Short term memories become long term memories. This is what gives us clarity, and space to take in new information when a new day dawns.

We sleep for so many hours so that our body can restore itself by repairing any damage and growing our muscles whilst we’re not using them.

Got any cuts or scrapes?

They’re going to take a lot longer to heal if you don’t get enough sleep.

We also need sleep for survival, it’s not just a luxury, it’s a necessity. Sleep is akin to recharging the batteries on an electronic item. With constant  usage, the power will become more and more depleted until the charge runs out and the item is unusable. 

There are different stages of sleep which all serve vital functions and help our body to recharge and recover ready to go again the following day. You can learn more about this by watching my video below.

Your lifestyle will play a deciding role in how much recovery your body requires.

There are also certain techniques which can help you to fall asleep faster, so that you make the most of your time in bed.

If you are an athlete who trains daily, a good amount of quality sleep is vital for the repairing and growth of muscles. The mental focus such an endeavour requires also needs to be processed during sleep.

This is why when you have a bad night’s sleep, your mood, focus and cognitive functions seem to desert you the next morning. 

The question of why we need to sleep has fascinated scientists and medical professions for centuries. It is only with the development of modern science that we have begun to understand just how integral getting enough sleep is to our physical and mental well-being.

If you live a life of little stress, practice mindfulness and mediation often, you can reduce your sleep quota. The body is able to recuperate when we are not asleep, but only if we are still, both in body and mind.

We spend around a third of our lives in a state of slumber. Why is that? Would we not be more productive if we were able to stay awake and do things 24 hours a day?

The universal law of polarity states that everything in existence must have its equal opposite. In other words, we wouldn’t know light without dark, hot without cold, loud without quiet. The same is true of sleep.

We wouldn’t know what it was like to be awake without sleep. Waking is turning on the switch, sleeping is turning it off. Each morning we wake up renewed, with a fresh day ahead full of opportunities. 

Wouldn’t life be a drag if there was no off switch?

What happens when we go without sleep?

Aside from being incredibly tired, depriving yourself of sleep has other consequences which can hinder your performance and impact your health.

It’s kind of a given that you’re going to be a lot less alert if you haven’t slept for a while, there’ll be a haze of exhaustion. You don’t even have to miss a lot of sleep for this to kick in, it might start to affect you if it was just a single particularly rough night.

We all have those moments when we just cant function, those times we desperately tell our minds to focus but just can’t see through the tired haze. This brain fog is amplified by a lack of sleep.

You can imagine how much worse it gets the longer you force yourself to stay awake.

It’s safe to say you’d have to rule out doing anything that requires any attention. This can be both frustrating and detrimental to performance in any given task.

What is usually an easy thing to accomplish can feel like an uphill struggle. We have to carry ourselves over the finish line, so to speak.

Your vision can also start to be affected as a result of lack of alertness, become blurred, not too dissimilar to the feeling we get after a few alcoholic drinks!

Just as you cant focus on the present, you start to forget things too. You may not remember that conversation you had only five minutes ago, or you may forget the one important thing you were supposed to do today.

Lack of sleep impairs your memory. Especially in the short term.

This was indicated in the aforementioned case of Randy Gardener in 1965. At the time, the then 16-year old high school student was attempting to beat the previous record of going without sleep for 260 hours. He was under constant monitoring and supervision by a doctor and Stanford sleep researcher.

Incredibly, the young man eclipsed the record and was able to stay awake for 264.5 hours in total. This however, didn’t come without costs. The doctor put Gardener through a series of tests throughout this sleepless period.

Two days in, the doctor noticed that Gardener’s vision was impaired and his eyes struggled to remain focused on one thing. He also displayed signs of ataxia which is the inability to repeat simple tongue twisters.

By day three, his mood plummeted, and by the fifth day he began to have hallucinations. Paranoia, irritability and trouble concentrating also became apparent from the man’s behaviour. Numerical tests also showed that his short-term memory was shot to pieces. He even had trouble remembering simple counting sequences and would forget what the task at hand was altogether.

It’s safe to say that Randy Gardener showed incredible willpower to accomplish the record, but I think we can all agree that it’s not a good idea to copy him!

If you’re mind hasn’t had the time to sort through your memories, as it usually does when you sleep, then it’s a lot more difficult to take in new memories, there’s simply not enough space.

You’ll need a hell of a lot more food to make up for the energy you’re using to stay awake. For a lot of people this links to weight gain, a side effect that would put anyone off staying awake for too long!

The longer you leave it without sleeping the worse your side effects will be. A couple of days or more without sleep could see you struggling to form simple sentences, and even hallucinating.

There are also links to premature ageing and lack of sleep, as the sleep period is vital for cell regeneration. Again, to use the battery analogy, you wouldn’t expect your laptop or phone to last very long if you constantly charged it to only 5% then drained it again and again.

There are more severe consequences as well, to do with your long term health. Your heart will struggle under the strain of exhaustion, your metabolism will slow down and you’ll be at higher risk of high blood pressure and developing cardiovascular disease. Not something any of us want.

Though there haven’t been any cases of death definitely caused directly by lack of sleep in humans, in animals long term sleep deprivation has lead to their demise. Those with fatal familial insomnia, which I’ll move onto in a moment, have died, but it’s unclear whether this is a direct result of sleep deprivation.

Considering these side effects can begin after just one sleepless night, the risks are definitely enough to put you off trying it for longer. The thrill of staying awake suddenly seems a lot less impressive!

Is it possible to FORCE yourself to stay awake?

For a night or two we can push ourselves to stay awake for whatever reason, maybe you’ve had a couple of wild nights in a row, or maybe you’ve got a deadline coming up and just cant afford to waste time in bed. But any more than that and it becomes incredibly difficult.

Even after just one night of sleep deprivation there are notable effects on our immune system, and our ability to focus, as shown in this study. In fact, sleep deprivation doubles the likelihood of making errors and multiplies the lapses of attention threefold.

You can force yourself to stay awake using caffeine or other stimulants, but this makes things like driving a car or operating machinery much more dangerous. It’s a risk that is often not worth taking.

Some tasks which we are able to do on auto-pilot may not be negatively affected by lack of sleep, but our decisions making and learning capabilities will be.

Forcing anything in life is generally a recipe for bad results, especially when it comes to natural bodily functions such as sleep. If absolutely necessary it can be done, but should be done with caution to avoid potential disasters from occurring.

Your mind will actually start to just shut down, and that’s when you’ll find yourself falling asleep involuntarily, like toddlers when they fall asleep with their face in their dinners. It takes a lot to fight your body when it knows what it needs.

Research has shown that somewhere between 10 and 20% of all road crashes are directly related to fatigue. This alarming fact underlines the risks involved with forcing yourself to stay awake, especially if you need to drive the next day.

The term “microsleeping” has been coined to describe a common happening that occurs when drivers are deprived of sleep at the wheel. A microsleep happens when a person slips into sleep for between two and thirty seconds without having any recollection of it happening.

Warning signs of microsleeping include increased difficulty focusing, heavy eyelids, yawning, eyes beginning to roll and the relaxation of neck muscles which causes the head to droop.

In many countries, governments have implemented laws which prevent people from working long shifts with little breaks in between, especially in the industries which utilise machinery or where driving is necessary.

In years gone by, truck drivers who were travelling long distances would force themselves to stay awake with the use of amphetamines and other stimulants. Thankfully this was made illegal a long time ago, and stricter regulations were introduced to stop people from being put at risk by tired drivers.

The real danger of forcing yourself to stay awake in any situation is that your decision making capabilities are significantly diminished. You lose the ability to rationalise and this can put yourself and others at risk.

So it is possible to force yourself to stay up, as Randy Gardner did for 11 days, but remember that that’s a world record. It’s not easy and anything more than a couple of days  will have harmful effects.

Fatal familial insomnia (FFI)

Fatal familial insomnia is an exception to the normal amount of time we can go without sleep. It is neurological disease that means you literally can’t sleep. It’s caused by a mutation of a protein and can develop spontaneously. You’ll be pleased to hear though that it is incredibly rare, with only around 100 people in the world suffering from it.

FFI is the one case where it is possible to stay awake, but it’s not a choice. Those diagnosed are completely unable to sleep, regardless of how tired they are, and it’s not pleasant.

However, it is one of the clearest indicators of how important sleep is and how dangerous it can be to go without it.

This rare genetic condition causes the brain to gradually degenerate. It start with mild symptoms which may seem like normal insomnia, then progresses to cause significant damage to both the mental and physical well being of the sufferer.

The autonomic nervous system, which is the part that controls automatic bodily processes such as breathing, sweating and regulating heart rate can be significantly affected. But what causes FFI?

The cause of fatal familial insomnia is genetic, but it can sometimes seem to occur randomly with no prior warning. Don’t worry too much – the chances of getting it are extremely slim, but it is worth studying to really see the grave truth of what sleep deprivation does to the body.

There are four stages:

  • Increasing insomnia – this stage lasts for 4 months.
  • Panic attacks, paranoia, hallucinations – all continue for around 5 months.
  • Unable to sleep at all – this goes on for around 3 months and causes extreme weight loss.
  • Dementia, and loss of voice and responsiveness – this happens over 6 months.

After these stages, unfortunately death ensues. Life expectancy from the onset of the disease is 18 months.

The sleep disorder insomnia is much more common and much less serious, but is also a good indicator of how important sleep is to our quality of life.

Oftentimes, people who suffer from insomnia simply find it difficult to get to sleep, stay asleep or a combination of the two. This may be down to racing thoughts, restlessness or simply not feeling tired.

A side effect from insomnia is that the people who suffer from it don’t feel refreshed after waking, even if they do manage to get to sleep. This results in symptoms such as fatigue.

Insomnia is the most common sleep disorder, with around a third of all adults reporting symptoms. Only 10 percent of adult’s symptoms are severe enough to be diagnosed with the disorder, though.

What does insomnia tell us about the importance of sleep and how much we need?

People who suffer from insomnia commonly report symptoms such as mood changes, irritability, fatigue, depression and anxiety.

Again, it’s also common for these people to have trouble concentrating on tasks in their daily life.

It’s worth noting some of the things that insomniacs are advised to change about their lifestyle in order to prevent episodes from occurring, or to relieve the symptoms. These include:

  • Avoiding strenuous activity or exercise around bedtime
  • Avoiding caffeine before bedtime
  • Avoiding screens (especially blue lights) in the hours leading up to bedtime
  • Minimising the time spent on their bed when not intending to sleep

Even for those who don’t suffer from insomnia, this advice should be followed in order to promote a healthy amount and good quality of sleep


For the majority though, the answer to how long we can go without sleep is not very long. More than a couple of days and the effects can become quite severe. We wouldn’t want to stay awake though, doing an all nighter is one thing, but depriving yourself of multiple nights of rest just isn’t something anyone would want to do, and not something you’d be able to do without a lot of difficulty either.

Over a long period of time, sleep deprivation can lead to serious health consequences. So be sure to listen to your body, and give it the ample amount of rest it requires in order to function properly.

People like Randy Gardner have bravely shown us that the human body is capable of staying awake for much longer than originally thought possible. However, experts have categorically advised against anyone attempting such a feat again due to the negative effects he showed during the experiment.

Our bodies know what we need, if we feel tired, usually we have the sense to go to bed, no matter how many things tempt us to stay awake.