How Much Sleep Do You Actually Need?

Find out how many hours of rest you should aim for, according to sleep experts.

You've probably heard that getting enough sleep is crucial, and it's true that sleep deprivation can have negative impacts on your health. "If [you] don't get adequate amounts of sleep at night, [you] don't let [your body] enter into the recovery stage to replenish energy, to metabolize nutrients and function properly when [you're] awake," explains Dave Rabin, M.D., Ph.D., a neuroscientist and psychiatrist. TL;DR: Sleep is like a reset button for your body.

Even if you're aware that sleep is essential, you might be grappling with a separate question: How much sleep should you get in a night? Here, experts explain how much sleep you should be getting and what you can do to improve your sleep quality.

How Much Sleep Do You Need Each Night?

You've probably heard the popular recommendation to aim for eight hours of sleep a night. However, the recommendation may not be derived from reliable studies, and it might not be right for everyone, according to Chester Wu, M.D., psychiatrist, sleep medicine doctor, and medical reviewer for Rise Science. The guideline is based on observational studies with self-reported data, and people aren't always accurate when determining the amount of sleep they got, says Dr. Wu.

Seven to nine hours per night is a more appropriate sleep recommendation, and different people will fall in different places within that range, according to Michael J. Breus, Ph.D., A.B.S.M., clinical psychologist and member of the scientific advisory board for Apollo Neuroscience. However, you don't have to put a ton of effort into pinpointing exactly where you fall within that range, according to Breus. If you feel refreshed and not in dire need of a coffee or energy drink to feel awake, it's safe to assume you got enough sleep. Additionally, you don't need to worry too much about figuring out how much sleep you need by age, since sleep needs are relatively fixed throughout adulthood, according to Dr. Wu. Research suggests that getting less sleep with age is the norm, but that doesn't mean that the amount of sleep you need necessarily declines, according to an article published in the Nature and Science of Sleep.

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Though seven to nine hours per night is generally accepted as the proper amount of sleep for adults, there are some cases where you may require even more rest, such as when you're sick, pregnant, or recovering from strenuous exertion (e.g., running a marathon), says Dr. Wu. On the other hand, if you get fewer hours of sleep than your body requires for multiple days in a row, you might go into sleep debt. Eventually, that debt may prompt you to make up for lost sleep by getting extra hours of sleep in one day — you have an innate biological drive to do so, adds Dr. Wu.

In these instances, getting extra sleep to make up for the occasional bout of sleep debt is totally fine, even if that pushes over nine hours. You can skip an alarm and sleep in, but a better option is to go to bed earlier or take a nap (no longer than a full sleep cycle of roughly 90 minutes) to ensure you make up for the loss of sleep without pushing back your bedtime, says Dr. Wu.

It bears mentioning that you shouldn't solely focus on how many hours of sleep you need, but also on ensuring that you're getting quality sleep. Sleep quality isn't just affected by total duration of sleep, but also the extent of interruptions and amount of time spent in each stage of the sleep cycle, as Shape previously reported. Modifiable lifestyle factors can have an impact on your sleep quality, says Dr. Rabin. "Not moving enough during the day will make you sleep less at night because that energy you would normally burn from moving around builds up inside the body," he says. "Exercising during the day and getting your heart rate up for at least 15 to 30 minutes (doing something active but safe) is very important to ensure you sleep well at night. Also, eating too close to bed will make it harder to sleep at night because your body is digesting food and not diverting resources to sleep."

How to Determine If You're Getting Enough Sleep

There is only one true way to know if you're getting enough sleep: paying special attention to how rested you feel upon waking up. When you get enough sleep, you feel refreshed and ready to power through your day without relying on stimulants such as coffee. You may want caffeine but not need it, which is a good sign that you're getting enough sleep, says Dr. Rabin. Also, if you feel like you always fall asleep immediately when you're head hits the pillow, that's a sign that you're not getting enough sleep, as Shape previously reported.

The most recognizable signs of sleep deprivation are daytime drowsiness and fatigue, according to Breus. "Daytime sleepiness can also cause excessive yawning, frequent blinking, eye rubbing, and even dozing off," he shares. Additionally, if you find that your memory, mood, and concentration feel a bit off, it can be due to a lack of sleep, which makes it difficult to regulate your mood and may intensify feelings of anxiety or depression, adds Breus.

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Note that if you wake up feeling refreshed but end up tired, say, in the middle of your work day, that's perfectly normal, according to Dr. Rabin. "It's okay to feel a little bit tired, especially after meals, and it's okay to feel a little tired if you've been working for a long time and paying a lot of attention to something and starting to feel exhausted…that's normal," he confirms. Although you may not have exerted much energy physically, your brain requires energy to function, which is why exhaustion may kick in after locking in on a task.

When appearing alongside other symptoms, a pattern of excessive sleep may be a sign of physical health conditions, says Dr. Wu. In this case, you should speak to a medical professional to determine whether an underlying health issue may be causing your fatigue.

No matter if you feel refreshed with just seven hours of sleep or never go without nine hours at minimum, the important thing is that you get the amount of sleep that you need to power through the day. Listen to your body, as it'll indicate if you should spend less time scrolling through your social feeds in bed and more time getting rest.