35 Fun Facts About Sleep That Will Fascinate You

Sleep is a mysterious thing, and even with today’s scientific advancements, there’s still so much we don’t know about the phenomenon. But what we do know may fascinate you. Some of these mysteries may leave you wondering, some may even scare you, and some can be fun to know.

Knowing the fun fact is always interesting to us, especially when we talk about the human body. You never know what can help you solve your own sleep problems or make it more interesting when you go to take a sound sleep.

Fun-Filled Facts About Sleep

Fun-Filled Facts About Sleep

So, here are thirty-five fun facts about sleep to blow your mind.

  1. The average human spends one-third of their life asleep; that’s the equivalent of around twenty-five years!
  1. Cats sleep twice as much as their human companions, around 15-16 hours per day. That’s a whopping two-thirds of their lives. Cats are crepuscular animals, which means they’re most active during twilight hours and spend much of the day dozing.
  1. Insects sleep, but not quite like we do. Instead, insects rest in something called a torpor state, where they display lowered metabolic activity, responsiveness, and body temperature.
  1. Whales and dolphins sleep with just one side of their brain. The other half stays in a wakeful state, remembering to breathe at the water’s surface to avoid drowning.
  1. Sleep cleans out our brains. While asleep, cerebrospinal fluid is pumped around the brain to wash away toxins built up during the day.
  1. The ancient Greek philosopher Aristotle believed that sleep was a direct result of digesting food and that a person only awakened from sleep once digestion was complete.
  1. The scientific name for talking in your sleep is somniloquy. It’s one of the most common types of parasomnias (abnormal sleep behaviors) and is most common in children and adolescents.
  1. Another type of parasomnia is somnambulism, otherwise known as sleepwalking. Most people who sleepwalk remember very little, if anything, about their nighttime escapades. Still, scientists think that the underlying cause could be linked to genetics.
  1. That startling feeling of falling that sometimes happens while you’re asleep is called a myoclonic jerk. Scientists still aren’t sure why it happens. Still, things like excess caffeine consumption, stress, and anxiety can make myoclonic jerks more frequent.
  1. The average person has between four and six different dreams each night. But most of us only remember a fraction of them, if any at all.
  1. Sleep deprivation has the same effect as drinking alcohol. It slows reaction times and impairs judgment, reasoning, and awareness. That’s why it’s so important to avoid driving while tired.
  1. Before the rise of the industrial revolution, most Europeans slept twice in one night. The first sleep, sometimes known as the ‘dead sleep,’ began just after sunset and lasted three to four hours.

    Then, around midnight, it was time to wake up and do a few chores, be intimate with a partner, say a few prayers, or enjoy a sip of home-brewed ale. Then, it was time to retire again for the second sleep, or ‘morning sleep,’ until the sun came up to mark the start of a new day.
  1. Most of us can’t sneeze in our sleep. This is because when our brains enter a sleeping state, our neuroreceptors, which trigger the sneeze reflex, are temporarily disabled.
  1. Somniphobia is the fear of falling asleep or being asleep. Most people develop this unusual phobia as a result of sleep disorders such as sleep paralysis and nightmare disorder, as well as PTSD.
  1. The scientific name for a sleep study is polysomnography. Polysomnography monitors patients’ vital signs and records their brain wave activity while in a state of slumber to help diagnose various sleep disorders.
  1. One of the earliest sleep studies was conducted at the University of Chicago. Nathaniel Kleitman is known as the Father of American Sleep Research, and he opened the world’s first sleep lab here in 1925. He later discovered the phenomenon of rapid eye movement (REM).
  1. Hawaii is the most sleep-deprived state in the US. Just 54% of Hawaiian residents get the recommended seven or more hours of shut-eye each night.
  1. On the other hand, Minnesota is the most well-rested of all the American states, with just 29.1% of the population clocking in less than adequate sleep.
  1. Globally speaking, Japan and South Korea are ranked as the lightest sleepers of all, with most of the population getting less than six hours per night. To tackle the problem, the Japanese have built nap time into their culture. ‘Inemuri,’ or sleeping in public, is commonplace, and many even view falling asleep at the office as a sign of dedication and hard work!

    Over in Korea, napping during the day is also encouraged, with trendy new ‘sleep cafes’ popping up all over the country.
  1. Human beings are the only mammals who can actively fight off sleep, even when they’re exhausted. When tiredness hits the other mammals in the animal kingdom, they’ll crash out as soon as it’s safe to.
  1. The longest recorded period a human being has ever gone without falling asleep is eleven days. The world record holder is Randy Gardner, who in 1964 stayed awake for an unthinkable 264 hours.
  1. Sleep deprivation is a killer. So, while Randy Gardner’s world record is impressive, don’t go attempting it at home. Humans can survive for much longer without food than sleep, and it doesn’t take long before the body’s vital systems begin to shut down.
  1. People who were born blind often usually suffer from a sleep disorder called Non 24, which leads to trouble falling asleep at night, and staying awake and alert during the day.

    This is because our circadian rhythms rely on light to signal to our brains when it’s time to fall asleep and when it’s time to wake up. But this mechanism is disrupted for people with no way to perceive light.
  1. A lack of sleep can cause you to pile on the pounds. When you’re sleep-deprived, hunger-regulating hormones such as leptin and ghrelin are thrown out of whack. This makes you more prone to snacking and less likely to feel full after a meal.
  1. The average person gets 0.3 inches taller when they’re lying down asleep in bed. But as soon as it’s time to get up, gravity pushes their skeleton back to its normal size.
  1. Many people struggle to fall asleep during a full moon. It was once thought to be due to moonlight’s effects on circadian rhythms. Still, the phenomenon persists in windowless sleep labs with no light influence from the outside environment. And so, scientists are still perplexed as to why and how this happens.
  1. If you’re a chronic oversleeper, you may have hypersomnia. Hypersomnia is a sleep disorder that causes you to sleep for long periods. You may also struggle to get up in the morning and feel overly tired throughout the day.
  1. Sleep is good for your memory. A lack of sleep is linked to cognitive impairment, including short-term memory loss. Still, by changing your sleep habits and getting the recommended hours of shut-eye each night, you can boost your brain back into tip-top shape.
  1. In Greek mythology, Hypnos is the god of sleep. Legend has it that he lived in a large cave surrounded by poppies and other sleep-inducing plants.
  1. Some people sleep with their eyes open. It’s not a common way to sleep, but it does happen, and doctors call it nocturnal lagophthalmos. Most people with nocturnal lagophthalmos don’t realize they have it until someone else notices and points it out. But if you regularly wake up with sore, dry eyes, it’s worth investigating if this could be the cause.
  1. Science has shown that women need around twenty minutes extra sleep per night than men. The reasons for this are still unclear, but some researchers believe it may be due to women’s tendency to multitask throughout the day.
  1. Sleep deprivation has been used as a form of extreme torture for centuries. It’s thought to cause more suffering than any other torture, and when used continuously, it always results in death.
  2. Sea otters hold hands while they sleep, which is both adorable and practical at the same time. Otters sleep on their backs, on the surface of the water. And so, by holding hands, they stay within the group next to their mate or pups.
  1. Every year on the 9th of March, the US celebrates National Nap Day. The tradition was started in 1999 by William Anthony, a professor at Boston University, and his wife Camille, and it’s still going strong today.
  2. Even more widely celebrated than National Nap Day is World Sleep Day, an annual celebration of sleep and sleep science. Created by the World Sleep Society in 2008, the international event aims to raise awareness of sleep issues, including sleep hygiene, sleep disorders, and the latest cutting-edge sleep research.


Sleep is a fascinating subject that is shrouded in mystery, and science still has a long way to go before we can understand the true nature and function of this universal phenomenon.

For more fascinating sleep facts and information, check out our wide range of blog posts about sleep hygiene, sleep environment, and sleep disorders.

Do you have any interesting sleep facts that we’ve missed from this list? Could you drop us a comment in the box below?

Sarah Wagner

I'm Sarah Wagner, and I founded Sweet Island Dreams in 2022. It's a blog dedicated to helping people mental vacation virtually anytime they want. By providing information about the best sleep of your life, I help people drift away to paradise without ever having to leave their bed!