Explainer Link Copied 12.31.24

How to Know If You’re Actually Getting Enough Sleep

How much can your sleep tracker really tell you? ByCarolyn Todd

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By now, we all know that sleep is pretty damn important. (The endless stream of sleep tracking products has made that abundantly clear!) Getting enough shut-eye is crucial for your mental and physical health—as well as just, you know, feeling like a human. And big shifts in your sleeping patterns can even be a tip-off that you’re dealing with depression or anxiety (among other things). 

But—quick question—how do you actually know if you’re getting enough sleep? Is the magic number really eight hours? Should you use a sleep tracker? (How accurate are those things anyway?) Should we all be getting sleep studies just in case?

We checked in with some sleep experts to answer all these questions and more.  

How much sleep do you really need? 

We hate to tell you that your whole life has been a lie but…that blanket eight-hours recommendation isn’t necessarily right for all of us. 

“Everybody needs a different amount of sleep, and a person needs different amounts of sleep at different times in their life,” says Jade Wu, PhD, a board-certified behavioral sleep medicine psychologist. 

How much rest you need largely depends on your genetics and age, Dr. Wu says. For example, your bestie might biologically need only seven hours of sleep to be well-rested, while your body genuinely requires nine. (Research shows there are even people who feel just peachy on four to six hours, thanks to certain genetic mutations.) 

Also worth noting: “we require less and less sleep as we age,” says Alicia Roth, PhD, a clinical health psychologist at the Cleveland Clinic who is board-certified in behavioral sleep medicine. In general, experts recommend teens ages 14-17 get eight to ten hours, adults 18-64 get at least seven hours, and adults over 65 get seven to eight hours, according to the National Sleep Foundation (NSF). (Again, these are just general recommendations.) 

How to know if you’re getting enough sleep 

OK, so how do you know if you’re getting what your body needs? It’s actually pretty straightforward. “The easiest and really the only way to tell whether you're getting enough sleep is by how you feel during the day,” says Dr. Wu. “Are you feeling sleepy?” 

Before you roll your eyes and tell us that you’ve been tired since 2019, hear us out. Sleepy isn’t the same as regular tired, experts say. “Tired is like, you’re dragging, you don't have energy, you don't feel up to it,” Dr. Wu explains. “You might feel exhausted and lethargic. But if you actually try to lay down and sleep, you can't. Because you’re not actually sleepy.” 

Being sleepy means that you could legitimately doze off right now if given the opportunity. “Or maybe if someone put on a boring enough movie, you could,” Dr. Wu says. “That means you’re not getting enough sleep.” And if you are actually taking naps and still struggling to keep your eyes open? You’re definitely underslept, says Shelby Harris, PsyD, a licensed psychologist in New York who specializes in behavioral sleep medicine. 

Obviously, it’s common to feel both tired and sleepy if you’re not snoozing enough. But tiredness on its own can be caused by things like stress, boredom or dehydration, Dr. Wu says—whereas sleepiness only comes from not getting enough sleep (or enough good quality sleep (more on that later).

A few quick caveats here: If you feel like you could go back to bed right after waking up, don’t sweat it. “Often people judge how well they slept last night by how they feel first thing in the morning. But that first half hour is not supposed to feel good,” Dr. Wu says. Unpleasant as it is, it’s normal to feel groggy and a little out of it for the first 30 minutes or so of your day, Dr. Wu says. It’s OK if you get a bout of drowsiness in the afternoon too, she adds—that’s just the rhythm of your body’s inner clock.

Also: If you’re only able to keep your eyes open with an ungodly amount of cold brew, you could still be underslept. Guzzling a lot of caffeine “might mask your natural sleepiness,” Dr. Wu explains. “So unmedicated alertness is what we're looking for.”

Other signs you might be underslept include a crabby mood, difficulty concentrating, and shaky short-term memory, Dr. Roth says. But something like moodiness “can be due to a million things,” Dr. Harris points out, like stress or depression. (And it’s pretty common for poor sleep and mental health issues to overlap, Dr. Roth notes.) That’s why sleepiness is the main red flag. 

Can sleep tracking products tell you if you’re sleeping enough? 

“Yes, but with a grain of salt,” Dr. Wu says. For instance, if you just want to know how much sleep you're getting, “a wearable can probably tell you that,” Dr. Wu says. While some tracking devices are more accurate than others, Dr. Harris says that most have gotten pretty good at telling you the total amount of time your body is asleep. (At least for the average, healthy, young or middle-aged person. Dr. Wu says we don’t have much data on how accurate these devices are in everyone, like people with sleep disorders or older people.)

How do these wearables work, exactly? “None of them are actually directly measuring sleep,” Dr. Wu says. (That would require an EEG to measure your brain waves.) Instead, they’re guesstimating using cues from your body that indicate whether you’re likely asleep or awake—like your body position, movements, heart rate, and heart rate variability. 

Pros caution that the only number you want to really trust is your total sleep time, though. They’re more skeptical when it comes to sleep stages and sleep quality grades (like your sleep score or body battery). These numbers are “kind of arbitrary” and haven’t been vetted by sleep scientists, Dr. Wu says. “I wouldn’t say they’re completely useless for sleep staging, but they’re not very reliable across the board,” Dr. Harris adds.

So a wearable can certainly satisfy your curiosity about sleep quantity. And if you’re working on clocking more hours at night and want to hold yourself accountable to that goal, a tracker can help, Dr. Wu says. 

But what a tracker definitely can’t tell you is whether the amount of sleep you’re getting is enough for you, Dr. Wu says. For example, if your tracker tells you you’re only averaging six hours, but you feel bright-eyed and bushy-tailed during the day, you’re probably not sleep-deprived. Or if it says you’re clocking a solid eight hours but you feel sleepy all day, you might be somebody who needs nine hours to function well, or you might even be dealing with an undiagnosed sleep condition. So while these wearables can help validate how you feel during the day and give you something to discuss with a provider, they shouldn’t be the only metric you take into consideration. 

How do you know if you’re getting good quality sleep? 

Let’s say you (and maybe your sleep tracker) are pretty sure you’re getting eight or more hours of sleep a night, but you’re consistently sleepy as hell throughout the day. It’s possible that you’re not getting good quality sleep. The surest sign is if you’re sleeping a lot, but still feeling sleepy all day, Dr. Harris says. 

A few more signs of bad quality sleep include snoring, frequent nightmares, kicking or thrashing a lot, waking up often, grinding your teeth, or getting up to use the bathroom a lot. These are all hints that you might be dealing with a sleep disorder, Dr. Harris says. 

A sleep tracking device could potentially offer some clues, too. While, again, sleep scores or grades might not be totally trustworthy, other data points can indicate less-than-awesome sleep quality. For instance, “It can show that you’re moving around a lot or waking up frequently,” says Dr. Roth. Certain sleep tracking products can also show a drop in oxygen levels or an elevated heart rate, Dr. Harris adds. (All potential symptoms of a sleep disorder.) 

What to do if you’re not getting enough sleep 

If you’re worried you’re slacking in the sleep department, it’s normal to look around for possible solutions. And there are tons out there right now—from natural sleep aids and supplements to various sleep products that promise to turn your bedroom into a bedtime haven. And, of course, sleep studies are an option. 

But before you jump into all that, the experts suggest starting with some free and simple strategies. Like, oh, trying to actually get more sleep (maybe an hour) for a couple weeks and watch what happens. “Even start with 30 minutes more for a few days and see if that helps,” Dr. Harris says. 

To make this happen, you might need to polish up on your sleep hygiene, Dr. Harris says. You know the drill: Stick to a sleep schedule, limit alcohol and caffeine, get some movement during the day, avoid bright screens before bed, have a winddown routine, and keep your room dark, cool, and quiet, per the NSF. 

You can also keep a sleep diary for a couple of weeks (using a free app or template) where you record things like your bedtime, wake time, difficulty drifting off, caffeine or alcohol use, exercise, and sleep disturbances. You’re looking for “variables that influence a good night versus a poor night” and “patterns that you may be able to correct on your own,” Dr. Roth says. 

If this helps you get more sleep and curbs the urge to faceplant on your desk during the day: cool, problem solved. You were, in fact, needing more sleep. “But if that's not helping enough, then you want to see a doctor,” Dr. Harris says. What kind of doctor—and whether you might require a sleep study—depends on your problem.

If you simply can’t sleep more because you’re wide awake in bed for hours, then insomnia is probably to blame. All a sleep study would show is that you’re laying there awake, Dr. Harris points out. (Pretty unhelpful.) Instead, you’ll want to see a sleep psychologist or psychiatrist. They’ll probably treat you with CBT for insomnia, Dr. Harris says—a highly effective short-term therapy that includes behavioral changes and relaxation techniques. (If that’s not enough, medications may also help, she adds.) 

How to know if it’s time for a sleep study 

As comfy as the idea of sleeping hooked up to a bunch of wires in a cold, strange lab might sound, there’s really only one reason you’d need a sleep study: If your doctor suspects that a sleep condition is stopping you from getting enough good-quality sleep. 

So, if you’re getting what seems like enough sleep but you’re still battling daytime sleepiness, or if you’re experiencing any of those signs of poor sleep quality we mentioned (snoring, frequent nightmares, or waking up a lot), a sleep study is a good idea.  

You can start with your primary care provider or go straight to a sleep specialist (depending on your insurance situation). A PCP can screen you for potential sleep disorders, including the most likely culprit, per Dr. Wu: Sleep apnea. (It affects about 26% of people between the ages of 30 and 70, according to the American Academy of Sleep Medicine.)

When you have sleep apnea, your breathing stops and starts, waking you up many times (usually without you remembering), and preventing you from reaching those deep, restorative stages of sleep, according to the Mayo Clinic. “You can sleep nine, ten hours but still feel very sleepy during the day,” Dr. Wu says. 

If your doctor suspects sleep apnea or another type of sleep disorder (like narcolepsy or parasomnias), they’ll send you to a sleep specialist who can order a sleep study and figure out what’s going on.

What do these mystical sleep studies entail? There are two types: At-home and in-lab. Doctors will usually opt for an at-home sleep test if you show signs of sleep apnea, Dr. Wu says. You get to sleep in your own bed and wear some nifty equipment to sleep for two or three nights, which measures things like how often you stop breathing, Dr. Wu explains.

The second kind of sleep study is called an in-lab polysomnogram. This is the whole shebang, or “the gold standard sleep study,” as Dr. Wu puts it, and it can be used to detect sleep apnea and the other sleep disorders we mentioned above. You’ll sleep overnight in a lab wearing a bunch of sensors, while somebody monitors things like your brain waves, eye movements, body movements, and heart rate, according to the Mayo Clinic. 

While this test only captures one night, it provides the full picture of what’s happening whenever you sleep, Dr. Wu says. A sleep study will tell your doctor if you’ve got a condition that’s been wreaking havoc on your sleep. And, of course, how to treat what’s going on—so you can start snoozing smoothly at night, and rejoin the land of the living during the day.