How Long Can You Go Without Sleep?

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Sleep is one of the basic needs humans have to satisfy in order to stay healthy, and, in the end, to remain alive. However, while we are good about ensuring we get the food and water – in various different forms – our bodies need to remain functional, sleep is something far too many of us do not take as seriously, and skipping and skimping on sleep has become something of a 21st century health crisis. But how long can you go without sleep?

There is no single answer to this question, because it’s very complex. However, in terms of numbers, the longest recorded period anyone has managed to stay awake is 264 hours – about 11 days – a dubious record set by a 17-year-old, Randy Gardner, for a school science fair experiment in 1965.

Gardner apparently suffered no long term health complications, and was ‘back to his usual self’ after a few days of good sleep. He did however show significant cognitive decline in the final days of his experiment, and began to lose control of his fine motor skills and even his perception of reality. Other, more recent, controlled experiments have seen people stay awake for eight to ten days with similar results. 

While the prolonged lack of sleep did not seriously compromise Randy’s health, this was a one off for scientific research. The problem is that an increasing number of ‘busy’ people are depriving themselves of the sleep they need on a near daily basis, and, for them, the story can turn out rather differently.

How Many Hours of Sleep Do You Need Each Night?

Very little about sleep science is exact, especially as it has only been taken seriously for the last few decades. Sleep itself is also not a standard bodily function: people sleep slightly differently from one another, and some seem to do better on less sleep than others.

Three different scientific bodies interested in sleep science – the National Sleep Foundation, the American Academy of Sleep Medicine and the CDC – have all come up with basic guidelines for the ideal amount of sleep humans should strive for at their various stages of life, and these guidelines can be roughly compiled for easier reading and comprehension as follows:

  • Newborn (0–3 months): 14–17 hours (National Sleep Foundation) No recommendation (American Academy of Sleep Medicine)
  • Infant (4–12 months): 12–16 hours per 24 hours (including naps)
  • Toddler (1–2 years): 11–14 hours per 24 hours (including naps)
  • Preschool (3–5 years): 10–13 hours per 24 hours (including naps)
  • 6–12 years: 9–12 hours per 24 hours
  • 13–18 years: 8–10 hours per 24 hours
  • 18–60 years: 7-8 hours per night
  • 61–64 years: 7–9 hours per night
  • 65 years and older: 7–8 hours per night

What Happens When You Don’t Sleep?

Randy Gardner’s record setting sleep deprivation session was not particularly monitored well, as the science – and tools – to do so were extremely limited nearly sixty years ago. Much of what is known about how he and his brain reacted to getting no sleep for eleven days is anecdotal, based on the recollections of the teen and observers.

As sleep science has progressed, more and more formal studies into the effects of sleep deprivation have been undertaken, and researchers and sleep medicine practitioners have a better idea about just what not getting any sleep can do to the human mind and body.

These efforts are complicated by the fact it is hard to define precisely what being asleep is in each individual that might participate in these experiments. We sleep in cycles, and so even if a person appears to technically be awake the chances are good that in as little as 18-24 hours they will begin falling into short periods of what scientists call overwhelming sleep – when motor functions are significantly impaired to the point of non-function – that may only last for a few minutes.

This is what happens to drivers on long hauls who ‘doze off’ at the wheel – often causing significant harm to themselves and others – and to students who seem to be sleeping in class. If you have gone for long periods without sleep, you are probably familiar with this ‘dozing off’ feeling, and with the disorientation that follows when you ‘wake’ again.

The Mental and Physical Side Effects of Sleep Deprivation

Sleep is necessary for both your physical and mental health. And while there is no standard for what might happen to a person going without sleep for set increments – 24,48,72 hours etc. – at some point (long before Randy’s record setting 11 days) your health will suffer.

Most of the immediate ‘side effects’ of sleep deprivation are mental and cognitive. These can set in quickly, as we mentioned earlier, and often include the following:

Decreased alertness.

Even missing 1.5 hours can make a difference in how you feel.

Excessive drowsiness during the day.

During the day, it can make you sleepy and fatigued. You may even doze off for several minutes at a time without even realizing that you have done so. Some people have been observed to begin to hallucinate in as little as 24 hours awake, and certainly in the case of Randy Gardener’s ‘experiment’ observers said he had ‘lost touch’ with reality in just a few days

Memory impairment.

Sleep deprivation can impair your capacity to think, remember, and process data. It’s the thing that many students do not realize, that staying up all night studying will not help their chances of acing a test, it will actually hurt them.

Stress in a relationship.

A lack of sleep can make you moody and increase your chances of having confrontations with people.

Decreased life satisfaction.

You may find it difficult to engage in routine everyday activities or exercise. You will begin to limp lethargically through your day

There’s a higher chance of a car accident.

According to the National Highway Traffic Safety Administration, drowsy driving causes thousands of collisions, injuries, and deaths each year. This has become a particular problem in the trucking industry worldwide.

In terms of the physical side effects of sleep deprivation, people suffer most when they make sleep deprivation a habit. This is to say that they do get some sleep, but not enough to meet their body’s needs. Those who, for example, follow the current craze for getting up at 4am but then try to stay awake well into the evening.

In these people, all kinds of health issues have been observed, including:

  • High blood pressure
  • Type 2 diabetes
  • Obesity
  • Decreased immunity and resistance to disease
  • Loss of libido and/or impotence
  • Stroke
  • Death

That last one sounds dramatic, but increasingly a lack of sleep and various attempts to stay awake artificially are resulting in death.

For example, in 2017, a popular Twitch gamer, a 35-year-old man given to broadcasting marathon gaming streams, and known to smoke and drink a lot during these sessions, died of “heart complications due to sleep deprivation.” after one 22-hour session. A number of other such cases have been recorded elsewhere in the world.

Chronic sleep deprivation, by the way, can also have a serious effect on your appearance, giving weight to the old adage that people need to get their beauty sleep. A constant lack of sleep has been shown to lead to premature, and deeper, lines and wrinkles, decreased skin tone and, as you probably know, unattractive dark circles under the eyes. Teens are also affected by chronic sleep deprivation – their sleeping needs are greater than adults and their natural sleep schedule is is generally later than the sacrosanct school schedules.

So, How Long Can You Go Without Sleep and Still Function?

However, many times they are told it’s a bad idea. Many people, claiming they are too busy to sleep, or don’t need to sleep as much as others, make sleep deprivation a habit. And many of those people claim that they do fine in terms of function.

For example, the long serving British Prime Minister Margaret Thatcher claimed to never sleep more than four hours a night. More recently, former President Donald Trump has claimed the same thing (although some aides have disputed that fact.) Other people who claim they do not sleep more than 4-5 hours a night include Twitter founder Jack Dorsey, and fashion designer Tom Ford.

As people do, science has shown, have differing sleep needs, these people may be telling the truth. They may also be taking naps during the day, or simply trying to show off how hard they work.

For most people, though, 24 hours is usually enough to result in mental decline that can be observed to impair their function. Those trying to stay awake longer also often do so by consuming excessive amounts of caffeine, not just in the form of that old stand by coffee but also via larger amounts of heavily caffeinated energy drinks, things which can add to their long term health risks.


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