Sleep Facts

Written by Ashima Yadav

Last Updated June 13, 2024

We spend about one third of our life sleeping, yet there is so much that we don't know about it. Sleep experts are still figuring out information regarding sleep; every day, we discover new facts about sleep. The knowledge about sleep, dreams, sleep disorders, etc., have gained some advancement over the last 25 years, yet we are not 100% sure about why we need sleep.

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Sleep is a vast subject for research, and even though there's so much we don't know about it, there's still so much that science has established. So, let's look at sleep facts and figures that will help us better understand sleep.

interesting sleep facts

Sleep Mechanism

Two internal physiological processes regulate sleep: circadian rhythm and sleep-wake homeostasis. These two work in coordination and regulate your state of sleep and wakefulness.

cicardian rhythm

Circadian rhythms are 24-hour cycles that keep on working in the background as per the body's biological clock. These rhythms control various things like the state of wakefulness, metabolism, hormones, and body temperature. These circadian rhythms signal your body when it's time to fall asleep and when it's time to wake up.

Sleep-wake homeostasis directs your body when it needs to sleep, reminding the body to sleep after a specific time. The more hours you spend being awake, the stronger the sleep drive gets and makes you fall into a deep sleep for longer duration after sleep deprivation.

Stages of Sleep

stages of sleep
  • Stage 1: This stage is a bridge between wakefulness and sleep, wherein heartbeat, eye movement, and breathing slow down, and muscles relax.
  • Stage 2: This is a stage of light sleep before you enter deep sleep. Here, muscles relax even further, eye movement stops, and body temperature drops. This stage is where you spend almost half your time sleeping.
  • Stage 3: This is a stage of deep sleep where your body completely relaxes and starts healing itself. This stage can be challenging to wake up from, and if you wake up in the middle of stage 3, you might experience brain fogginess.
  • Stage 4: This is Rapid Eye Movement (REM) stage which is associated with dreams. Rapid side-to-side eye movements, increased brain activity, breathing rate, heart rate, and blood pressure to near wakefulness state mark this state. This stage is mostly referred to as rem sleep.

Here are some interesting facts about sleep:

woman sleeping in bed

1. Sleep is a survival need, just like food and water.

If you have pulled all-nighters while studying for exams or finishing up some work, you know how it feels to go too long without sleep. Lack of sleep can hinder your ability to function in daily life and therefore is a basic necessity. You can go longer without food than without sleep. The longest anyone has ever gone without sleep is 11 days 25 minutes, while the longest period one has gone without food is 382 days.

2. You should fall asleep after 10 minutes of hitting the bed

maintain a sleep schedule

On average, it should take 10-20 minutes to fall asleep. You're probably sleep-deprived and worn out if it takes less than five minutes. On the other hand, if it takes more than 20 minutes for you to fall asleep regularly, you should make a sleep schedule and have sleep hygiene so that you can catch the much-required sleep.

3. Think you don't get dreams?

Well, if you think so, you might find yourself wrong here because everyone gets about 4-5 dreams every night. However, we forget almost 95% of our dreams shortly after waking up.

Another interesting fact about dreams is that not all of us dream in color. In fact, before color television came, most people used to dream in black and white. Now, only 12% of people dream in black and white.

4. Blind people dream too.

You must have wondered about it sometime or the other; if not, we got you wondering now. Anyways, the answer to this is yes, blind people dream too. However, their dreams might not be visual, especially if they're blind by birth. Instead, their dreams include other sensations like touch, smell, hearing, etc.

5. Post-lunch sleepiness

If you have ever felt like taking a nap after lunch, you're not alone, and no, you're not just being lazy. Post-lunch sleepiness is a real thing. Our body naturally feels a drop in energy and tiredness peaks at 2:00 a.m. and 2:00 p.m. However, it would be best if you didn't wait till 2 in the morning to feel tired before sleeping. Instead, maintain a sleep routine and go to sleep on time to get at least 8 hours of sleep.

6. Variation in sleep required by different animals

The amount of sleep required by any organism depends on various factors like their body size, environment, diet, age, etc. To discuss the extremities in the variation, koala bears sleep for about 20-22 hours a day, while elephants require only 2 hours of sleep per night. Humans require about 7-8 hours of sleep per night.

7. Effect of light on circadian rhythms

effect of light on circadian rhythms

Exposure to blue light has the strongest effect on circadian rhythm and can create difficulties in falling asleep. In addition, this light exposure affects melatonin production, explaining why and how it affects circadian rhythm. However, exposure to sunlight during day time can boost alertness.

Dim lights like yellow, orange, red, etc., have little impact on sleep. Therefore, if you're using your devices late in the evening, you can turn on 'reading mode' or download applications that filter out the blue light.

8. Negative effects of sleep deprivation

Sleep deprivation makes you moody and grumpy and affects your cognitive abilities like concentration, memory, critical thinking, etc. Studies show that being awake for 17 hours straight is similar to having a blood alcohol level of .05%. This is the reason why sleep deprivation is also a reason behind increased traffic accident, because it creates difficulty concentrating.

Sleep deprived people are at an increased risk for various serious disorders like heart attack, high blood pressure, diabetes, etc. Moreover, it also affects your skin and makes it look dull over time.

Another interesting fact about sleep is that humans are the only mammals that willingly delay sleep. Despite knowing the adverse effects of sleep deprivation, humans delay sleep and suffer the consequences.

9. Insomnia: difficulty in falling asleep

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Insomnia is a sleep disorder characterized by difficulties in sleeping and staying asleep. This inability to sleep even when you're tired and your body needs rest can result in fatigue and many other health issues like hypertension, diabetes, weight gain, etc.

Insomnia is one of the very common sleep disorders, found in 10-50% of the population worldwide. And you'll be surprised to know that insomnia is not something that just humans face; even a few animals are seen having issues in falling asleep.

10. Sleep apnea

It is a condition wherein your breathing stops while you're asleep. This activates a reflex in your brain that wakes you up enough for you to continue breathing. Though it keeps you alive, it interrupts your sleep cycle and prevents you from having a well-rested, good night's sleep.

English bulldogs are the only canines to experience this condition. It happens because of their weird anatomy.

11. Somnambulism

Somnambulism or more commonly known as sleepwalking, is a condition where a person walks and moves around while asleep. Most people outgrow it in their teen years; however, some adults also experience sleepwalking.

12. Dysania

a young girl finding it difficult in getting out of bed in the morning

We all face difficulty in getting out of bed in the morning. But did you know there is an actual term for that feeling? Well, yes, it is a real condition called dysania. It refers to the inability to get out of bed or the desire not to leave the bed even after you have woken up. This causes people to have trouble waking up.

13. Sleep paralysis

Sleep paralysis is a state when you're just sleeping or about to wake up, where you are conscious but unable to move. It is experienced by 7.6% of the population in their lifetime. Sleep paralysis causes sleep disruptions and may induce a fear of sleeping among the people who experience it.

14. Somniphobia

Somniphobia is an extreme fear of sleeping. It is characterized by anxiety and obsession over avoiding sleep throughout the day. People with somniphobia have underlying causes like sleep apnea, sleep paralysis, nightmares, PTSD, etc.

15. Association between sleep positions and sleep quality

sleep position and sleep quality

Some researches have found that certain sleeping positions may be better than others. Sleeping in fetal position, wherein your legs and hands are pulled closer to each other, is considered one of the best positions to sleep in. Whereas, sleeping on stomach is considered the worst position to sleep. Even when sleeping on side, it's found to be better to sleep on your left side as compared to right side, cause sleeping on right side may sometimes cause acid influx.

If you're not getting proper sleep or you wake up with back ache, you may want to consider changing your sleeping position.

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The more you understand about sleep, the more quality sleep you can get

Did you know any of these facts beforehand? Even if you did know some, we're sure you got to know some more interesting facts about sleep. However, the best thing about sleep is that the more knowledge you gain about it and the more insights you get into it, the better your sleep quality gets. So, we hope that this blog will increase your sleep quality to some extent.

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Disclaimer: What is said in this article has been referenced from multiple sources and is intended only for educational and informational purposes. Please note that no content in this article is a substitute for professional advice from a qualified doctor or healthcare provider. Always consult an experienced doctor with any concerns you may have regarding a health condition or treatment, and never disregard any medical suggestions or delay in seeking treatment because of something you read here.