How Much Sleep Do You Actually Need?

Tired? We all know the feeling; irritable, groggy and exceptionally lazy. Chances are you didn’t sleep enough last night, or the past few nights. But what exactly is “enough sleep?” And more importantly, can you ever “catch up” on it? While the very function of sleep is still debated by scientists, we do know that it’s necessary to function efficiently and productively. After all, we spend 24 years of our lifetime sleeping, it had better be important. Researchers have tested how much is required each night by assigning groups of people to four, five, and eight hours of sleep over extended periods of time. After 14 days, those with eight hours of sleep exhibited few attention lapses of cognitive issues; however, those with six or four hours of sleep showed a steady decline. In fact, after only two weeks, the six hour group showed a similar reaction time to a person with a blood alcohol concentration of 0.1%, which is considered legally drunk. The four hour sleepers suffered even more, occasionally falling asleep during their cognitive tests. In both groups, brain function decreased day by day, almost linearly with no sign of leveling off. Scientists have dubbed this cumulative effect as sleep debt. So can we recover from it? After a night or two of little sleep, studies show that the body and brain can fully recover with a few nights of good sleep. However, with long term sleep deprivation on the scale of weeks to months, the recovery of cognitive function is much slower, requiring many more nights of quality sleep. On the timescale of months to years, it is unknown whether brain function can be fully repaired, or if it causes permanent damage. Paradoxically, with chronic sleep deprivation, your sleepiness or how tired you feel does eventually level off, meaning that you become less and less aware of your objective impairment over time. So how long should you sleep? Most studies tend to show that seven to eight hours of sleep is the average ideal for humans. Apart from the cognitive issues, individuals who consistently sleep less than seven hours a night have an increased risk of heart disease, obesity and diabetes, not to mention a 12% higher risk of death. On the flip side, studies have shown that while sleeping more than eight hours does not impair brain function, it also carries an increased risk of heart disease, obesity and diabetes, and a 30% increased risk of mortality! So too much sleep may also be a bad thing. But variation most certainly exists, and our genetics play a large role. In fact, individuals genuinely unaffected by only six hours of sleep were found to have a mutation of a specific gene. When scientists genetically engineered mice to express this gene, they were able to stay awake for an extra 1.2 hours than normal mice. It turns out these short sleepers have more biologically intense sleep sessions than the average person. Ultimately, while it’s important to know the ideal average of seven to eight hours exists, let your body and brain help you figure out its own needs. After all, no one shoe size fits all. If you want to know how to get better quality sleep each night in order to conquer the hurdles of sleep deprivation, we have some tips and research for you over on ASAPThought. You can find a link in the description below to that video. Thanks to for giving you a free audio book of your choice at Audible is the leading provider of audio books with over 150,000 downloadable titles across all types of literature. We recommend the ‘A Song of Ice and Fire’ series, which the Game of Thrones TV show is based off of. It’s kept us up through the nights and caused a lot of lost sleep! You can download this audio book or another of your choice for free at And with a subscription you can get one free book a month, so you can read the whole series! Special thanks to Audible for making these videos possible. And subscribe for more weekly science videos!

99 thoughts on “How Much Sleep Do You Actually Need?”

  1. "oh I'll be fine, i get an easy 7 and a half hours of sleep!"
    college: bind bund buined, your sleep schedule is ruined

  2. I get home at 8 pm from extracurricular stuff. Eat dinner. Finish school homework. Get ready to sleep. 12-1 am. I wake up at 6.

  3. I sleep alot like 8-9 hours but that is because there is no school now. Yay 😀 Holidays!

  4. Im trying to sleep early but in the end i just wake up early. my body doesnt let me sleep 8 hours. i always sleep like 5 hours a day.
    whats wrong with me😫😫

  5. I wanna know if my sleep deprivation is causing me to hallucinate at 2:44 when I'm reading the word "better"…

  6. Surprisingly I can go on like 3~4 hours of sleep and still feel energetic and awake,I though this was normal until my friends complained that they cant get less than 8 hours. This is actually convenient because I ultimately have more time to do other stuff such as homework or anything else.

  7. I am a 10 year old and I sleep like an adult and I am a human and it said humans need 7-8 hours of sleep

  8. ok believe it or not we have to wake up at 4:50-5:00 am for school everyday (i woke up at 4:30 am for graduation bc i had to get ready) and i’m only 14-30 minutes away from my school because school starts at 6:55 and i get picked up the normal time

  9. Well I am in my last year at school and my exams are two days away and I am having a lot of troubles with sleep.. so If anyone can help or have a tip I would really appreciate it
    Thank a lot

  10. I have the easiest way to fall asleep turn on Surah al baqarah close your eyes relax get into a comfortable position it works I promise

  11. Your body is like a battery when you are sleepy the battery goes to 3% then when you sleep you recharge the next day

  12. I sleep usually about 6 hours and i feel great when i wake up
    I start sleeping usually at 1 and wake up at 7 for school

  13. Woah guys I just had a crazy thought. So woah we do stuff and then all of a sudden the nation just switches off like woah. How crazy is that. Imagine how much crime can be done when people go sleepsleep

  14. Oh, I didn't sleep enough. I'll guess I'll sleep a bit more than 8 hours to repay my sleep debt.
    Scientists: You wanna die?

  15. But its depended on age because babies or young children cant sleep for 8 hours because they wold feel bad

  16. Oh this is really scary. My aunt does nights most days of the week, she's been doing this for a few years now. Guess she has unrepairable cognitive brain functions 🤷

  17. Video: showing you how much sleep you need daily
    Me: watching video for relaxing ok I'm going to bed goodnight

  18. Well in 4 hours I have to get out of the house because someone is coming to look at our house to see if they want to buy it ….

  19. Well i all ready have diabetes i hade it for 3 years and i have school in 7 or 8 days 😭 i can't sleep 😭😭😭😭😭😭😭😭

  20. I call bullshit on that mutation that allows you to sleep less with no repercussions, I'm sure such ppl exists, but the explanation sounds stupid, a gene codes a protein, a mutated gene codes an slightly different protein, even if the protein is folded differently, the net effect would be the variation in concentration of the original protein or it's absence in favor of a different protein.

    See the problem? if by regulating the concentration of one protein you could just like that cut the sleep requirement of a person by two hours, pharmaceutical companies will go nuts on it, that kind of supplement could potentially become standard around the world.

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