The science of how much sleep you actually need


Getting plenty of sleep each night is important to maintaining a healthy and productive life. But how much sleep do you actually need?

Joe Avella and Jessica Orwig tackle this question on the Facebook series "Science the $#!* out of it."

For the average adult, the National Sleep Foundation recommends 7 to 9 hours of sleep a night.


Today, however, many Americans are sleep-deprived, which can have significant adverse effects on physical and cognitive functions.

The reason why some people don't get enough sleep can be accredited to busy modern lifestyles. But there are other reasons too.

It turns out habits such as using electronic devices or drinking alcohol right before bedtime can be detrimental to getting a good night's sleep.


Learn more on how to get better sleep on this episode of "Science the $#!* out of it." Following is a transcript of the video.

Jessica Orwig: Joe!

Joe Avella: Wh- what?


Orwig: What's wrong?

Avella: I'm exhausted, I got like no sleep last night. Only two or three hours.

Orwig: That's not enough.


Avella: Well, how much is enough?

Orwig: Well, you're gonna find out. 'Cause we're on ... Science The $#!* Out Of It.

Orwig: So, how much sleep do you usually get a night?


Avella: With the tossing and turning, and waking up all the time, pretty close to like five.

Orwig: Yeah, you definitely are sleep deprived.

Avella: I can't help it. It's not like I can't get into the bed. It's just like my mind is still just going like super-fast. Like, oh, you shouldn't have said that. You shouldn't have done that. Oh, your stepdad was right. You don't know what you're doing. This and that, like oh, like, oh, the cat, my money, I'm poor and I'm unhealthy, and boom, boom, boom. Next thing you know it's like 3:00 AM and I'm like, "Oh, crap."


Orwig: Some people have a hard time sleeping at night because they have reduced levels of melatonin in their system. Melatonin is called the sleep hormone. Night owls, for example, don't actually start producing melatonin until much later in the night, which is why they don't feel tired until later.

Avella: I've seen videos, and I've heard people brag about how they only need like four hours of sleep, and they're, like, totally rested, whatever. Is there, like, a set amount of time that everyone needs sleep.

Orwig: Yeah, so you're the average adult, like how old are you?


Avella: Twenty-three?

Orwig: An average adult between the ages of 18 to 64 needs about 7 to 9 hours of sleep a night, according to the National Sleep Foundation. So it's just your overall quality of life is gonna be lower if you are sleep deprived.

Avella: Yes, true, but staying up late totally rocks.


Orwig: What do you do late at night that's so important?

Avella:- Surf the internet. I'm literally looking at a screen until the second before my head hits the pillow.

Orwig: No, that's a bad thing. I mean the screen right in front of your face right before you go to bed. That's ... For years scientists knew that light affects sleep, but they didn't necessarily know how. And then in 2002, they discovered a different kind of sensor in our eyes. It's called the intrinsically photosensitive retinal ganglion cells. These cells are extremely sensitive to blue light. Which could explain why one study found that people who don't have electronic light in their life, their circadian rhythms, their sleep cycles, actually synced up to the rising and setting of the sun. But because we bring these phones to our bed, we're looking at this light, specifically, the blue light in those phones is sending a signal to our brain that it's daytime out, which is making us feel more alert, less tired, and ultimately disrupting our sleep.


Avella: Okay, now what about drinking alcohol before going to bed? 'Cause sometimes to help me go to sleep I kinda like to bada-bing a few, you know?

Orwig: Drinking alcohol can make you feel tired, because it actually elevates the amount of adenosine in your body, and adenosine is one of those chemicals that makes you feel tired. So it can help you fall asleep, but once you are asleep, that's where the problem starts. So we have a sleep cycle, where we cycle in between non-REM and REM. And we cycle between that about five times a night. Alcohol blocks your ability to have REM sleep. But if you don't get REM, you're not going to feel as alert the next day, so nightcap's probably not the best thing.

Avella: Do I wanna fall asleep fast and feel bad, or take forever to fall asleep and feel bad?


Orwig: There are some foods that you can eat that will help you fall asleep if the reason you're having trouble with that is because you have lower melatonin levels in your body. And there are some natural foods with a relatively significant amount of melatonin. So there's almonds, there's raspberries, and goji berries actually have quite a bit as well.

Avella: Goji berries? What would be a couple of things to throw at me that I should do to like, probably help me to get better sleep?

Orwig: The number one thing that experts always recommend is the same bedtime every night.


Avella: No, I hate that note.

Orwig: I mean, you just have to set out a time. Live, you really should say, "Okay, 30 minutes "before bed, I'm not gonna look at my screen, "I'm not gonna turn on the TV." Just like, open a book. You can even-

Avella: What? Books? No. Are you kidding me?


Orwig: You can do-, you should also probably-

Avella: No, forget that.

Orwig: If you're ...


Avella: Screens only. It's TV, or iPad, or phone, or laptop, or some sort of monitor. That's everything now, I'm not gonna pick up a book. What am I gonna ... and then read by candlelight?

Orwig: Well then, continue having terrible sleep.

Avella: Fine, I will.