15 Little-known Facts About Sleep

Posted Jun 07, by Val Liarikos [+]

When you sleep, you grow by about 8mm!

However, this growth is just temporary, the next day you shrink back to your former height.The reason is that your cartilage discs are squeezed like sponges by the force of gravity when you stand or sit. Here's some other cool facts about your body:

  • Your stomach's digestive acids are enough to disolve zinc. The cells in stomach lining renew so quickly that the acids don't have time to disolve it.
  • A block of bone the size of a matchbox can support 9 tons of weight. That's 4 times as much as concrete can support!
  • The focusing muscles of the eyes move 100,000 a day. If you were to give your legs the same workout, you'd need to walk 50 miles a day!

Check out more cool facts at the source.


Some people are genetically coded to only need 4 hours of sleep!

We've talked about before how sleep is a mystery to scientists still. They have a hard time figuring out WHY we need to do it. Well, there's some people who have a genetic mutation called hDEC2, which regulates their sleep-wake cycle to be shortened to only 4 hours.

Most of us might be able to get by with sleeping only 4 hours for a little while, but eventually it takes a toll. These people are as refreshed as if you and I had slept for 8. Some of the people who are known or suspected to be short sleepers are Margaret Thatcher, James Franco and Martha Stewart.

Read more about this interesting mutation here.


People who are depressed spend more time in REM sleep!

There is a strong correlation between the amount of REM sleep a person has and depth of depression. The more REM sleep, the more negative emotions emitted. So, the earlier the REM sleep occurs in an individual, the more severe the depression is.

In some cases, the REM sleep can begin 45 minutes after falling asleep. That means these sleepers' first cycle of NREM sleep amounts to about half the usual length of time. This early REM displaces the initial deep sleep, which is not fully recovered later in the night. The displacement of the first deep sleep is accompanied by an absence of the usual large outflow of growth hormone.

The timing of the greatest release of human growth hormone is in the first deep sleep cycle. The depressed have very little slow-wave sleep, Stages 3 and 4 of the sleep cycle, and no big pulse of HGH; and in addition to growth, HGH is related to physical repair.

If we do not get enough deep sleep, our bodies take longer to heal and grow. The absence of the large spurt of HGH during the first deep sleep continues in many depressed patients even when they are no longer depressed.

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Sleepy-driving is as dangerous as drunk driving!

Drinking is probably the biggest and most heavily stressed “do not” when it comes to driving, and most people would never even consider sleep to have a negative correlation with driving, yet new data tells us otherwise!

If an average person gets less than six hours of sleep in a night they begin to have a slower reaction time, diminished coordination, and impaired judgment. This correlates to driving because it makes it more difficult to navigate a car when a person’s brain is not operation at it's full potential.

The legal limit for drinking and driving in most of Europe is a BAC of .05, which is about how impaired your brain is after not sleeping for 17 hours! Although America is slightly higher, usually around .08 or .1, scientists still acknowledge the dangers of not sleeping and operating a car.

People who commonly work night shifts are especially at risk because they usually sleep a couple hours less and at awkward hours, making driving sober with little sleep more dangerous than being slightly intoxicated!

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If you don’t have cues for sleep time, your sleep cycle becomes 25 hours long.

We’ve all wished there were more hours in the day before. We just have too much to do and 24 hours isn't long enough. Well there may be a scientific reason that we feel this way.

Humans may be programmed for a sleep-wake cycle that is out of sync with the world's 24 hour day-night cycle. In 1938, two men, Nathaniel Kleitman and Bruce Richardson, decided they wanted to know how cave men slept.

In other words, how long would humans sleep and then stay awake if there were no external cues to tell them when to go to bed and when to wake up.

After searching for the perfect location that would completely isolate them from the outside world, they settled on a cave. Just like the cave men of prehistoric times. For 33 days, they stayed in the cave and let their bodies tell them how long to sleep.

What they found and what subsequent experiments have found is rather odd. They discovered that, when left to its own devices, the human body actually follows a 25 hour sleep-wake cycle rather than the 24 hour one that the world's turning dictates.

Read the source for more info on sleep and this study in particular.


Sleeping eight hours at once might not be the healthiest option!

A growing body of evidence from both science and history suggests that the eight-hour sleep may be unnatural. A psychiatrist conducted an experiment where a group of people were put in total darkness for 14 hours a day for a whole month. It took a while for them to regulate their pattern, but by the 4th week, they had settled for a very distinct sleeping pattern: they slept 4 hours, woke up for 2 and then slept for another 4.

Looking at historical data, it seems like that sleep pattern was not just widely accepted, it was also common knowledge. In fact, people used the time in between sleeps to talk or have sex. Doctors even recommended that time as the best time to conceive. It wasn't until the late 17th century that references to 1st and 2nd sleep started to disappear: it started in the upper classes and then it disappeared entirely by the 1920s.

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A device called the REM Dreamer lets you control your dreams!

Imagine being able to control your dreams? The REM Dreamer can get you pretty close! It’s a sleeping mask that allows whoever’s wearing it to become aware that they’re dreaming. The clever device does this through using infra-red sensors to detect when you’ve fallen into REM sleep and then uses light and sound to give you a reality check. This jogs you into becoming lucid in your dream setting!

The light and sounds will appear in the dreams as signs such as car headlights or sunlight. The really cool thing about the mask though is its ‘two way communication’ feature. This allows the wearer to actually signal back to the lucid mask that you have become conscious, so that it can stop giving you cues. The mask is likely to feel a bit weird at first. You can adjust the intensity, frequency and duration of the audio and light alerts though, to suit the varying sensitivities of different sleepers.

In the morning you can then check to see how many times it activated in the night! The REM Dreamer may not work for everyone, and can take some time to adapt to. If you stick with it though it can really enhance dream experiences and make sleep a whole lot more exciting! So, tempted? Check it out here.


There is a disease where you eventually stop sleeping and then die. There is no cure.

Hopefully you’re not an insomniac and/or hypochondriac. It’s called fatal familial insomnia, or FFI, and is a very very rare brain disease. It’s caused usually by a mutation to the PrPC protein, but can also happen spontaneously.

It begins with progressively worsening insomnia, followed by hallucinations, delirium, and then dementia. Once the symptoms begin, the average lifespan is anywhere between 7 and 18 months. Most often it’s genetic, and is so rare that it’s been found in just 40 families and about 100 people total since its discovery in 1765.

While one might think sleeping pills would help, but they’ve been proven to actually worsen the situation. Even an induced coma doesn’t work; it was attempted on a man in 1991 and his brain just wouldn’t shut down. In that case, when the man died, he hadn’t slept in 6 months.

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Lack of sleep makes you want to eat junk food!

You’re probably wondering how sleeping less could affect what foods you want to eat, but recent science points in the direction that the less you sleep, the more you’re body will want unhealthy foods. After studying 25 normal-weight volunteers who underwent sleep deprivation for five nights scientists were surprised to find the link between lack of sleep and junk food cravings. 

The pleasure-seeking areas of the brain reacted much more strongly when shown images of unhealthy food when sleep was limited, however when participants had a “normal” night of sleep their brains reacted the same to both healthy and unhealthy food images. Ever had to pull an all-nighter and stocked up on pizza, soda, and candy? 

That’s most likely because when your body undergoes extreme sleep changes it craves foods that will give it the highest caloric intake, or extremely unhealthy foods, resulting in late night, unhealthy binges. 

(Source) 


There's a drug that can let you stay up for 48 hours with no side effects!

It's called Modafinil and it's in a class of drugs called eugeroics. It's a stimulant in the same vein as caffeine and adenosine, but the difference in how it works the brain means it doesn't have the same side-effects that the others do. 

The way caffeine and Adenosine work is that they block certain receptors in the brain that react to dopamine, which makes it slow down. This means, for example, that coffee does not give you energy, but rather, doesn’t let the brain realize it needs more energy. This is why people crash after caffeine. The effect goes away and all the tiredness catches up to you. Modafinil doesn't have that problem.

No one really knows how it works yet, but it seems that instead of blocking the brain's dopamine processing, it just slows production of dopamine. On top of that, it also prevents the re-uptake of another neurotransmitter called noradrenaline, which triggers sleep.

The end result, and one of the most mysterious, is that modafinil doesn't trigger sleep debt. People who stay awake for a day or two on modafinil don't report a need to catch up on sleep after the effect wears off. They can sleep the normal amount!

There's a lot more to say about this, so check out the source if you're interested. 


In Pennsylvania, it is illegal to sleep on a refrigerator, but only outside.

You might not realize it, but there are actually quite a few laws determining how and when you can sleep. In fact, in Pennsylvania it is completely illegal to sleep on your refrigerator outside. 

If you are inside, however, it is okay to sleep on top of your refrigerator. Despite the discomfort of sleeping on said refrigerator, it is apparently done enough to warrant the writing of a law. In addition to determining where you can sleep, governments across the United States are determining how you’re allowed to sleep and what you can do to other people who are asleep. 

Here are some other strange laws about sleeping: 

  • In Oklahoma, it is illegal to wear boots to bed. They must be removed before falling asleep. On the flipside, wearing shoes is perfectly okay. 
  • In Washington State, you must ask permission before sleeping in someone else’s outhouse. That would be a cramped, smelly place to sleep! 
  • Not all laws apply only to humans sleeping. Horses also have laws to follow too. It is illegal to let a horse sleep in a bakery in Santa Ana, California.

To read more laws about sleeping go to this link

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The Strangers in Your Dreams are Actually People That You’ve Seen in Real Life!

The human brain is responsible for many complex creations, but it can’t invent the image of people. So the “strangers” that you meet in your dreams actually have the faces of people who you’ve once seen in your real life but forgotten, like your childhood mailman or that guy bumped into on the side walk that one time. 

Chances are that you’ve laid their eyes on more than a few individuals, and so the brain as a huge cast of characters to play with when you drift off to sleep. Except for in the case of extreme psychological disorder, every human being dreams. In fact, in a recent study, students who were awakened at the beginning of each dream but still allowed 8 hours of sleep, all experienced difficulty concentrating, irritability, hallucinations, and signs of psychosis in a span of three days. 

When they were allowed their REM sleep, their brains compensated for the lost time by increasing the percentage of the sleep spent in the REM stage. Dreams are a window into the subconscious. Even though most of the time, they’re completely random, disorganized, and we forget 90% of them within 10 minutes of waking up; many people have drawn inspiration from their dreams. Mary Shelly’s Frankenstein was a based on a dream that she had. 

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Not waking up a sleepwalker is more harmful than waking one up!

Sleepwalking is more common in children than adults and more likely to occur when one is sleep deprived. Sleepwalking happens when one is in a deep sleep and therefore they are more difficult to awake and most likely they will not remember sleepwalking. 

It is a misconception, though, that it is important to not wake up a sleepwalker. In fact, it could be quite dangerous if you don’t wake them up. Sleepwalkers do things from sitting up in bed and look around to walking out of their home and driving their car for long distances. Some medications and sedatives can increase the onset of sleepwalking. 

There is a higher prevalence of sleep walking in children who wet the bed than those that do not. There isn’t a cure for sleepwalking, though. Improving one’s sleeping habits and patterns can eliminate the problem of sleepwalking. Eliminating alcohol and certain medications can also lessen the likelihood that sleepwalking with continue. 

(Source)


Falling backwards in a nightmare can change it to a more pleasant dream.

It sounds like something out of Inception, but it’s true. Falling backwards while in a dream is a popular technique for awakening from an unpleasant dream, or changing the scenery of your unpleasant dream. 

There’s a whole guide to doing it correctly. It takes some time to learn to use well, and requires a few things to know beforehand. Falling backwards in a dream can sometimes cause a “false awakening,” where you think you’re awake but still dreaming. 

If you’re really committed to making the “falling backwards” technique work, you have to remember to do a reality check after falling backwards. It’s likely you’ll still be asleep, though. 

It’s important to make sure you’re thinking of a new “dreamscape” to fall into when you’re falling backwards, or else nothing will happen. Sometimes, a nightmare can be so bad that it wakes you up. 

But falling backwards from one nightmare into a better dream can ensure you won’t wake up. Closing your eyes is also recommended when falling backwards in a dream because it can help concentration.

It’s also recommended that you move intentionally when falling so that you can prepare yourself. The whole guide is very extensive, and if you’re interested, you can read moreat the source

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Some people have internal clocks longer than 24 hours. It's called the Non-24-hour Sleep-Wake Syndrome!

It’s a chronic sleep disorder and most often affects those living in a time-isolated facility with no time cues. It consists of a chronic steady pattern of one to two hour daily delays in sleep onset and wake times in an individual living in society.

The pattern of delay continues literally around the clock. It takes a week or two to complete a cycle. It causes nighttime sleepiness and excessive daytime fatigue and napping.  

(Source) 


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