How Much Sleep Do You Really Need?

March 17, 2021 | Casper Editorial Team
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Some days, you may wake up before your alarm feeling refreshed and alert, while others you’re hitting snooze until the last possible second. Even if you sleep a relatively consistent amount each night, you can feel dramatically different upon waking up.

So how much sleep do you really need? The solutions to your sleep frustrations lie in sleep cycles, which are the stages your body goes through each night as you doze off.

Understanding how much sleep you need is about optimizing your sleep cycle, age, and personal preferences. If you want to wake up feeling refreshed and alert, keep reading to understand how much sleep you really need. 

Sleep Guidelines by Age

The amount of sleep you need changes throughout your life. During developmental years, you need much more rest so your body can grow and restore. As you age, the amount of sleep you need decreases. Check out the chart below for a guide to ideal sleeping amounts based on your age.

Life Stage Age Hours of Sleep Needed
Newborns 0–3 months 14–17 hours
Infants 4–11 months 12–16 hours
Toddlers 1–2 years 11–14 hours
Young Children 3–5 years 10–13 hours
School Children 6–12 years  9–12 hours
Teenagers 13–18 years 8–10 hours
Young Adults 18–25 years 7–9 hours
Adults 25–64 years 7–9 hours
Seniors 65+ years 7–8 hours

It’s important to remember that the amount of sleep needed to feel well-rested can vary from person to person. While some adults can function well on six or seven hours of sleep, others need at least nine to feel like they can properly function. It’s important to evaluate how you feel after waking up to determine the amount of sleep that’s right for your body.

Stages of Sleep

stages of the sleep cycle chart

Your body goes through several cycles while you sleep. Each cycle is broken down into four phases: N1, N2, N3, and REM sleep. Each of these overarching sleep cycles takes an average of 90 minutes — which is why it’s generally recommended to coordinate your sleeping schedule with the number of sleep cycles you can complete.

For example, within the recommended 7–9 hours for adults, 7.5 hours of sleep equals five sleep cycles and nine hours of sleep equals six sleep cycles. 

  • Stage 1/N1: The shortest “transition” phase, N1 typically lasts only one to five minutes. During this phase, you may feel like you’re dozing off as your brain activity slows and you transition into sleep mode. 
  • Stage 2/N2: In stage 2, your muscles relax and your breathing and heart rate slow. Your eye movement stops, and it’s more difficult to be woken up by small external stimuli. N2 initially lasts for 10–25 minutes, but this stage can begin to be longer as you progress sleep cycles during the night. 
  • Stage 3/N3: During stage 3, you move into deep sleep. Your body further relaxes and moves into a restorative sleep that helps with growth and recovery. N3 typically lasts for around 20–40 minutes, but this time typically shortens throughout the night as you spend more time in REM sleep. 
  • REM Sleep: REM sleep is the final stage of your sleep cycle, during which your body undergoes several changes. These include rapid eye movement (REM), fast breathing, increased heart rate, and higher brain activity. REM sleep also typically corresponds with temporary paralysis, which is a protective measure to ensure your body isn’t harmed by trying to act out your dreams.

How Much REM Sleep Do You Need?

REM sleep should make up around 20–25% of your total sleep for the night, approximately 1.5–2 hours of sleep for a typical adult. On average, you undergo around three to five REM sleep cycles each night. Your first REM cycle typically doesn’t occur until 90 minutes into sleep, and the amount of time you spend in REM sleep gradually lengthens throughout the night.

Signs You’re Not Getting Enough Sleep

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Even if you don’t feel tired, you should still be looking out for warning signs of sleep deprivation. Sleep is an integral part of your health, and if you’re not getting enough it can severely impact your long-term health. Here are some warning signs that you might not be spending enough time with your pillow. 

  • Irritability or moodiness: Sleep deprivation can increase negative emotions and feelings of frustration or moodiness. In turn, your mood can affect the quality of your sleep, so if you’re going to bed feeling stressed or anxious, it could lead to a poor night of sleep. 
  • Fatigue: While the term “fatigue” may be used interchangeably with “tiredness,” you should know the distinction that fatigue is often associated with health problems, while tiredness is akin to being sleepy. If you’re getting the recommended hours of sleep but still feel fatigued, it may be worth consulting with a doctor to understand if you have any underlying medical issues.
  • Difficult focusing: If you feel like you haven’t been processing things well during the day, it may be because you didn’t get enough sleep. Sleep deprivation can make it more challenging to focus and can even impact your judgment and decision-making. 
  • Skin concerns: If you lack sleep, it can show on your skin. From dark undereye circles to increased acne, sleep deprivation can affect your hormones, which in turn show changes in your skin.
  • Fluctuating weight and appetite: Studies have shown that people who sleep less than six hours each night are more likely to be overweight, so if you suddenly see the scale changing, take a look at your sleep habits to see if they play a contributing role.
  • Fluctuating libido: A fluctuating libido can be a sign of profound fatigue within your body. If you’re consistently feeling too exhausted for intimacy, take a look at how you’re sleeping to diagnose why you’re experiencing this sudden change. 

Tips to Sleep Better at Night 

illustration of woman sleeping

If you suffer from sleep deprivation, it can be tough to diagnose the cause and find a solution. Learning how to fall asleep fast isn’t a one-size-fits-all game, which is why you should try different methods to figure out what works for you. 

Check out these tips to get better quality sleep and wake up feeling well-rested. 

  • Create a bedtime routine: Having a consistent bedtime routine can help you set your internal body clock, so you wake each day feeling refreshed and well-rested. Your body will learn to understand signals of when it’s time for bed, so you won’t have to deal with the sleep anxiety that comes with tossing and turning all night. 
  • Keep naps to 20 minutes: Napping is a beneficial way to reset yourself if you’re feeling worn out during the day. Just be sure to keep your power nap in the 20-minute sweet spot, so you wake feeling rested and productive instead of groggy. 
  • Sleep in a cool room: Sleeping in a space that’s too hot or cold can feel uncomfortable, and since your body temperature naturally cools at night, you’ll want to be in a cool room that feels just right. For ideal sleeping conditions, set your thermostat to 60 to 67 degrees Fahrenheit before going to bed. 
  • Avoid caffeine: Caffeine may be fantastic for starting your day, but having a cup of joe within six hours of bedtime can negatively impact your quality of sleep. Try to limit your caffeine intake for up to six hours before bed to avoid caffeine-induced restless sleep.
  • Turn off your tech: The blue light emitted from technology can signal to your body that it’s time to be awake. To help you wind down for the night, turn off your electronics one hour before bed. 

Sleep FAQs

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How to Sleep 8 Hours in 4 Hours?

If you want to learn how to sleep 8 hours in 4 hours, you need to hack your sleep schedule to get the most out of your rest. While you can’t turn back time, you can optimize your sleeping cycle by sleeping either three hours (two complete cycles) or 4 ½ hours (three full cycles). 
Setting your sleep schedule to your sleep cycles will prevent you from waking up feeling groggy and confused — instead, you’ll wake up feeling more alert and ready to take on the day. 

Is it OK to Get 5 Hours of Sleep?

While getting five hours of sleep isn’t ideal, it’s okay once in a while. However, five hours of sleep isn’t enough long-term, so don’t plan on a consistent five-hour sleep schedule. If you do need to sleep around the five-hour mark, try setting your alarm to allow for either 4 ½ or six hours of sleep — this will let you get in either three or four full sleep cycles respectively. 

Can You Adapt to Less Sleep?

If you’re trying to figure out whether you can adapt to less sleep in the long-term, you may be disappointed. While you can function on less sleep for some time, most adults are at their prime productivity levels when they sleep seven to nine hours per night. However, research has found that “banking” sleep, or racking up extra sleep before a less restful period, can help minimize the adverse effects of sleep deprivation for some time. 

How Many Hours is Oversleeping?

Oversleeping is defined as nine or more hours of sleep per night for adults. While oversleeping once in a while isn’t a big deal, consistently spending more than 9 hours asleep may be a sign of an underlying health issue, such as a mental condition like depression, or a sleep disorder such as bruxism and sleep apnea.

Is it Normal to Sleep 12 Hours?

Sleeping 12 hours as an adult isn’t recommended but can be fine once in a while. The most common reason for a prolonged sleep like this is lack of rest the previous nights. While sleeping a bit more on weekends isn’t uncommon, consistently sleeping 12 or more hours can be a sign that you’re getting poor sleep during the week — meaning your body is compensating for reduced quality sleep by spending a longer amount of time in bed.

To Each Their Own

So how much sleep do you really need? Well, the answer is that it depends. A growing child likely needs several more hours of sleep than their parent, but sleep is also unique to each individual. To determine how much sleep you really need, take a look at your sleeping habits to diagnose how well you’re sleeping and determine what you can do to sleep better.

Want to get the best sleep of your life? Starting catching some zzz’s with a cozy mattress and buttery-soft sheets today.