How long are you in rem sleep

REM & NREM, Sleep Stages, Good Sleep Habits & More

What is sleep?

You may think nothing is happening when you sleep. But parts of your brain are quite active during sleep. And enough sleep (or lack of it) affects your physical and mental health. When you sleep, your body has a chance to rest and restore energy. A good night’s sleep can help you cope with stress, solve problems or recover from illness. Not getting enough sleep can lead to many health concerns, affecting how you think and feel.

During the night, you cycle through two types of sleep: non-rapid eye movement (non-REM) sleep and rapid eye movement (REM) sleep. Your brain and body act differently during these different phases.

What happens in the brain during sleep?

Researchers continue to study sleep and its effect on us. While we’ve learned a lot about sleep, there’s still much that’s unknown.

We know that brain chemicals are very involved in our sleep cycle. Neurotransmitters are chemicals that help the nerves communicate. They control whether we’re awake or asleep, depending on which neurons (nerve cells) they’re acting on:

  • Neurons in the brainstem (where the brain and spinal cord meet) produce neurotransmitters called serotonin and norepinephrine. These chemicals keep our brain active when we’re awake.
  • Neurons located at the base of the brain are responsible for us falling asleep. It seems these neurons turn off the signals that keep us awake.

Why do we need sleep?

Sleep helps us in many ways. We need it for:

  • Growth: In children and young adults, deep sleep (sleep that’s harder to wake from) supports growth. The body releases growth hormone during this type of sleep. The body also increases production of proteins, which we need for cell growth and to repair damage.
  • Nervous system function: A lack of sleep affects our memory, performance and ability to think clearly. If a person is severely sleep deprived, they may even experience neurological problems such as mood swings and hallucinations. Sleep also helps our nerve cells. They can repair themselves, so they function at their best. And certain nerve connections get a chance to turn on, strengthening our brain and thinking ability.
  • Survival: Researchers don’t fully understand why sleep is so essential. But studies in animals have shown that getting deprived of REM sleep can shorten lifespans. Lack of sleep may harm the immune system, which protects us from infections.
  • Well-being: People who don’t get enough sleep are at higher risk for developing various health conditions including obesity, diabetes and heart problems.

What are the stages of sleep?

When you sleep, your brain goes through natural cycles of activity. There are four total stages of sleep, divided into two phases:

  • Non-REM sleep happens first and includes three stages. The last two stage of non-REM sleep is when you sleep deeply. It’s hard to wake up from this stage of sleep.
  • REM sleep happens about an hour to an hour and a half after falling asleep. REM sleep is when you tend to have vivid dreams.

As you sleep, your body cycles through non-REM and REM sleep. You usually start the sleep cycle with stage 1 of non-REM sleep. You pass through the other stages of non-REM sleep, followed by a short period of REM sleep. Then the cycle begins again at stage 1.

A full sleep cycle takes about 90 to 110 minutes. Your first REM period is short. As the night goes on, you’ll have longer REM sleep and less deep sleep.

What is non-REM sleep?

Three stages make up non-REM sleep.

Stage 1:

This stage of light sleeping lasts for five to 10 minutes.

  • Everything starts to slow down, including your eye movement and muscle activity.
  • Your eyes stay closed. If you get woken from stage 1 sleep, you may feel as if you haven’t slept at all. You may remember pieces of images.
  • Sometimes, you may feel like you’re starting to fall and then experience a sudden muscle contraction. Healthcare providers call this motion hypnic myoclonic or hypnic jerk. Hypnic jerks are common and not anything to be concerned about as this occurrence is unlikely to cause any complications or side effects.

Stage 2:

  • This period of light sleep features periods of muscle tone (muscles partially contracting) mixed with periods of muscle relaxation.
  • Your eye movement stops, heart rate slows and body temperature decreases.
  • Brain waves become slower. Occasionally, you’ll have a burst of rapid waves called sleep spindles.
  • Your body prepares to enter deep sleep.

Stages 3

  • This stage is deep sleep.
  • During this stage, your brain produces delta waves, very slow brain waves.
  • It’s hard for someone to wake you up during this stage.
  • You have no eye movement or muscle activity.
  • If you’re woken up, you may feel groggy and disoriented for a few minutes.

What happens during non-REM sleep?

During non-REM stages, your body:

  • Builds bone and muscle.
  • Repairs and regenerates tissues.
  • Strengthens the immune system.

As you age, you get less non-REM sleep. Older adults get less deep sleep than younger people.

What is REM sleep?

When you enter REM sleep, brain activity increases again, meaning sleep is not as deep. The activity levels are like when you’re awake. That’s why REM sleep is the stage where you’ll have intense dreams.

At the same time, major muscles that you normally control (such as arms and legs) can’t move. In effect, they become temporarily paralyzed.

Usually, REM sleep arrives about an hour and a half after you go to sleep. The first REM period lasts about 10 minutes. Each REM stage that follows gets longer and longer.

The amount of REM sleep you experience changes as you age. The percentage of REM sleep:

  • Is highest during infancy and early childhood.
  • Declines during adolescence and young adulthood.
  • Declines even more as you get older.

What else happens to the body in REM sleep?

Besides increased brain activity and muscle relaxation, your body goes through a series of changes during REM sleep. These changes include:

  • Faster breathing.
  • Increased heart rate and blood pressure.
  • Penile erections.
  • Rapid eye movement.

What affects sleep quality?

Chemical signals in the brain influence our sleep and wake cycles. Anything that shifts the balance of these neurotransmitters can make us feel drowsier or more awake. For example:

  • Alcohol may help people fall into a light sleep. But it reduces the deeper stages of sleep and REM sleep and leads to more disrupted sleep.
  • Caffeine and pseudoephedrine (drug ingredient) can stimulate the brain. They may cause insomnia, an inability to sleep. Watch out for caffeinated drinks such as coffee and drugs such as diet pills and decongestants.
  • Medications such as antidepressants can cause less REM sleep.
  • People who smoke heavily often sleep lightly and have less REM sleep. They may wake up after a few hours because they experience nicotine withdrawal.
  • Very hot or cold temperatures can disrupt REM sleep. We’re less able to regulate body temperature during REM sleep.

How much sleep do I need?

Many factors affect how much sleep you need. Age is a big factor:

  • Infants need about 16 hours a day.
  • Toddlers and preschoolers need about 12 hours.
  • Teenagers need about nine hours.
  • Adults need seven to eight (though some are fine with five and others need closer to 10).
  • Pregnant people often need more sleep during the first trimester.

What is a sleep debt?

If you haven’t slept well or long enough for a few days, you might create a sleep debt. Once your debt builds up, you may feel physically and mentally exhausted. Try to make sure you get enough sleep every night to avoid creating this debt. You can’t necessarily make up your debt by sleeping a lot on the weekends. It’s best to get enough sleep all week long.

Can we adapt to needing less sleep?

Generally, people don’t adapt to getting less sleep than they need. You may feel like you’re used to reduced sleep, but it still affects your function. For example, it can harm your judgment and reaction time.

What is sleep deprivation?

When you’re sleep deprived, you’re not getting the total amount of sleep you need. Signs of sleep deprivation include:

  • Falling asleep within a few minutes of lying down.
  • Feeling drowsy during the day.
  • Nodding off for microsleeps — short periods of sleep during the day when you’re otherwise awake.
  • Sleep deprivation can be dangerous. Driving while tired causes about 100,000 car accidents each year, according to the National Highway Traffic Safety Administration. It also causes 1,500 deaths. If you feel tired on the road, pull over. It’s not safe to drive if you’re drowsy.

What are sleep disorders?

According to the American Sleep Association, at least 40 million Americans experience sleep disorders each year. Another 20 million have occasional sleep issues. These disorders cause sleep deprivation, leading to problems with work, school, driving and social activities.

There are more than 70 sleep disorders. A few, known as disruptive sleep disorders, lead to moving around or making sounds. Other sleep disorders involve food. And some sleep disorders overlap with psychiatric conditions. If you have problems with sleep or feel very tired, talk to your healthcare provider about a possible sleep disorder.

Some of the most common sleep disorders include:

  • Insomnia disorder: Many people experience insomnia at some point in their lives, with trouble falling or staying asleep. Sleeping pills can help in the short-term but behavioral strategies to improve sleep including cognitive behavioral therapy for Insomnia (CBT-i) is a much better long term solution.
  • Narcolepsy: You may suddenly fall asleep during the day, even if you had a good sleep the night before. These “sleep attacks” can last a few seconds or up to 30 minutes. Talk to your provider about your symptoms and additional testing will need to be completed to diagnosis this sleep disorder.
  • Restless legs syndrome (RLS): You may feel unpleasant sensations in your legs (such as prickling or tingling). You may also have an urge to move your legs to get relief. If you have RLS, talk to your healthcare provider about medication to help improve symptoms.
  • Sleep apnea : You may experience periods of interrupted breathing while you sleep, a condition called sleep apnea. Often, getting polysomnography (sleep study) in a sleep center is the best way to get properly diagnosed and treated. Sometimes, weight loss or not sleeping on your back can help. But you may need a special device to help you breathe while you sleep.
  • Snoring: People who regularly snore can have disturbed sleep. They can also disturb the sleep of their bed partner. Snoring often leads to feeling tired during the day. Several treatment options are available for snoring.

What are good sleep habits?

Good sleep habits, also called good sleep hygiene, are practices to help you get enough quality sleep.


  • Have a sleep schedule: Go to sleep and wake up around the same time every day, even on weekends and vacations.
  • Clear your mind before bed: Make a to-do list early in the evening, so you won’t stay awake in bed and worry about the next day.
  • Create a good sleep environment: Make sure your bed and pillows are comfortable. Turn down the lights and avoid loud sounds. Keep the room at a comfortable temperature.
  • Exercise every day: Stay active but try to avoid exercising during the few hours right before bed.
  • Relax: Before bed, take a warm bath, read or do another relaxing activity.
  • See your healthcare provider: If you’ve been having trouble sleeping or feel extra drowsy during the day, talk to your provider. There are many treatments available for sleep disorders.


  • Consume caffeine, nicotine and alcohol late in the day: These substances can interfere with your ability to fall and stay asleep.
  • Lie in bed awake: It’s better to do a soothing activity, like reading, until you feel tired.
  • Nap during the day: A short nap (less than 30 minutes) is OK if you’re very sleepy. But try to avoid naps after 3 p.m.
  • Think negative thoughts: Try to avoid a negative mindset when going to bed, such as, “If I don’t get enough sleep now, I won’t get through my day tomorrow!”
  • Use electronics right before bed: Electronics, such as your phone or tablet, can interfere with your body’s production of melatonin. This hormone gets released before bed to help you feel tired.

A note from Cleveland Clinic

Far from being a state of doing nothing, sleep is an essential part of our lives. It helps our body rest, recharge and repair. There are four sleep stages — three in the non-REM phase plus REM sleep. Many factors can affect sleep quality, including the food and drink you consume before bed and room temperature. Many people experience trouble sleeping now and then. But if you think you may have a sleep disorder, talk to your healthcare provider. Common sleep disorders include insomnia (trouble falling asleep) and sleep apnea (breathing trouble during sleep). Your provider can help you get the diagnosis and treatment you need.

How Much Deep Sleep Do You Need?

How much sleep you need by age can range from 8 to 14 hours.
New research aims to identify not just how much total sleep you need — but also how much of each stage of sleep you need.

If you are getting the recommended amount of slumber — seven to nine hours a night — you spend about one-third of your life asleep.

Although that may seem like a lot of time, your mind and body are very busy during that time, so you can be productive, energetic, and healthy when you’re awake.

Five stages of sleep rotate between non-rapid eye movement (NREM) and rapid eye movement (REM) and include drowsiness, light sleep, moderate to deep sleep, deepest sleep, and dreaming.

Sleep stages 1, 2, and REM consist of light sleep, while 3 and 4 comprise deep sleep.

Stage 1

During stage 1, you drift from being awake to being asleep. This is a light, NREM sleep that doesn’t last very long. You may start to relax and dream, but may also twitch as you transition into stage 2.

Stage 2

Stage 2 of the sleep cycle is still a light sleep, but you are drifting into a steadier sleep. Your breathing and heartbeat slow down, and your muscles relax. Your body temperature decreases, and your brain waves are less active.

Stages 3 and 4

In stage 3, you enter deep sleep, and stage 4 is the deepest sleep stage. During deep sleep, your breathing, heartbeat, body temperature, and brain waves reach their lowest levels. Your muscles are extremely relaxed, and you are most difficult to rouse.

Stage 4 is known as the healing stage, when tissue growth and repair take place, important hormones are released to do their jobs, and cellular energy is restored.

REM sleep

Your first REM cycle of the night begins about 90 minutes after you fall asleep and recurs every 90 minutes. Your eyes move around quickly behind your eyelids and your brainwaves look similar to those of someone who is awake. Your breathing, heart rate, and blood pressure rise to near-waking levels.

REM sleep, often referred to as stage 5, is when you are most likely to dream.

Your arms and legs become temporarily paralyzed during this stage to prevent you from physically acting out your dreams.

In healthy adults, about 13 to 23 percent of your sleep is deep sleep. So if you sleep for 8 hours a night, that’s roughly 62 to 110 minutes.

However, as you get older you require less deep sleep.

During deep sleep, a variety of functions take place in the mind and body:

  • memories are consolidated
  • learning and emotions process
  • physical recovery occurs
  • blood sugar levels and metabolism balance out
  • the immune system is energized
  • the brain detoxifies

Without deep sleep, these functions cannot take place and the symptoms of sleep deprivation kick in.

On the other hand, there doesn’t seem to be any such thing as too much deep sleep.

How much REM sleep should you get

Although there’s no official consensus on how much REM sleep you should get, dreaming is most common during this stage. Experts believe that dreaming helps you process emotions and solidify certain memories.

For most adults, REM takes up about 20 to 25 percent of sleep, and this seems to be healthy during average sleep cycles. However, sleep research is raising some interesting questions. One recent study suggested that higher amounts of REM sleep may be associated with depression. But don’t go making sudden changes in your sleep habits — it is not clear which is the cause and which is the effect.

How much light sleep do you need?

Although sleep scientists believe that light sleep is good for you, there is no minimum to strive for. Light sleep is usually the default stage, one that is nearly impossible to avoid if you are asleep at all.

Too much overall sleep on a regular basis, however, is linked to obesity, depression, pain, heart disease, and even increased risk of death.

How much deep and light sleep do children need?

Babies and children need more sleep than adults. Babies need the most, spending about 16 of every 24 hours asleep. Approximately 50 percent of their slumber is spent in the REM stage, while the other 50 percent is divided between stages 1 through 4 and NREM sleep that cycles between light and deep.

As children grow older, the amount of sleep they need varies:

  • toddlers: 11 to 14 hours
  • preschoolers: 10 to 13 hours
  • school-aged children: 9 to 12 hours
  • teens: 8 to 10 hours

With enough sleep that appears to be restful, it’s likely that the light, deep, and REM ratio is exactly where it should be in young people.

If they’re having trouble with falling asleep, staying asleep, or sleeping well, or if they are sleeping way too much for their age, children may be irritable, could have learning and memory problems, or may be more susceptible to illness.

If you sleep 8 hours but toss and turn all night, you may not be getting enough deep sleep.

It’s impossible to force your brain to go into deep sleep, but there are a number of strategies that have shown some promise in terms of increasing your percentage of deep sleep. These include:

  • reducing stress
  • establishing sleep rituals and routines
  • using an eye mask to block out light
  • sleeping in a cool room
  • exercising
  • eating a healthy diet
  • listening to white or pink noise
  • brainwave entrainment
  • meditation

Although the science is still new, a number of sleep trackers are available that may help you track your sleep patterns and see how much light, REM, and deep sleep you are getting.

For more sleep support, check out our sleep shop.

According to the American Sleep Apnea Association, you should feel fresh and alert when you wake up, but many people don’t.

If you’re sleeping for 7 to 9 hours each night, but only 10 percent of that is deep sleep, you’re not getting the 90 minutes you need and might still be tired each day. A sleep study may help you figure out what is going on.

There are a number of possible causes that you might want to discuss with a doctor, including:

  • general sleep disorder
  • obstructive sleep apnea
  • not getting enough sleep
  • getting too much sleep
  • other health conditions that cause fatigue

Scientists say that quality sleep is as important to health as food and water are. It helps you to survive and thrive. Some of the side effects of sleep deprivation include:

  • memory troubles
  • mood changes
  • weakened immunity
  • trouble concentrating
  • poor response time and increased risk of accidents
  • high blood pressure
  • weight gain
  • risk for diabetes
  • low sex drive
  • risk of heart disease
  • poor balance
  • early aging

Scientists agree that sleep is essential to health, and while stages 1 to 4 and REM sleep are all important, deep sleep is the most essential of all for feeling rested and staying healthy.

The average healthy adult gets roughly 1 to 2 hours of deep sleep per 8 hours of nightly sleep. There are various ways to gauge whether you are, from personal trackers to a sleep study.

If you’re waking up tired on a regular basis, it’s a good idea to talk to a healthcare provider.

what causes sleep disorders and what to do

It seems that there is no person left who has not heard that the correct organization of sleep can do wonders for his productivity and well-being. But it also happens that 8, 10 and even 11 hours of sleep do not get rid of fatigue and weakness in the morning. We decided to ask the doctor about the causes of poor sleep and ways to deal with this problem.



Women Health

Doctor's advice

Healthy sleep

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Together with an expert, we understand the causes of poor sleep in adults and possible ways to cope with this problem.

Yuliya Yudanova

Head of the Medical Examination Department of BestDoctor

A night's rest refreshes and restores energy, if this is not prevented by sleep disorders. Some of them, like insomnia, are hard to ignore. But there are more insidious diseases that can cause poor sleep - many of them a person can not guess for a long time, especially if he lives alone.

If you sleep at least 7 hours, but are still completely broken in the mornings and nod off during the day, you may want to check for one of the following diseases. The sooner you figure out why you're not sleeping well, the better you'll start to feel.


What gives it away : pain in the jaw area, ringing in the ears, headaches in the morning, violation of facial aesthetics.

What happens while you sleep: rattling and gnashing of teeth during sleep.

Nocturnal bruxism is a cause of poor sleep in women and men characterized by excessive activity of the masticatory muscles leading to clenching of the teeth during sleep. If a person lives alone, he may not be aware of the problem until he begins to experience migraines and difficulty opening his jaws in the morning.


The causes of poor sleep can be very different - from genetic predisposition to stress and depression. According to various estimates, the problem is faced by 5 to 20% of the adult population, at risk are men from 25 to 50 years old. In addition to the fatigue of the masticatory muscles, which transforms into pain, people with this diagnosis note an increase in tooth sensitivity.

Where to go: with this cause of sleep disturbance, it is better to contact an orthodontist - he will help confirm or refute the diagnosis.

Obstructive sleep apnea syndrome

What gives it away: this sleep disorder is characterized by night sweats, fatigue in the morning, frequent urination, severe drowsiness and irritability during the day.

What happens while you sleep: With this cause of sleep disturbance, there is an abrupt cessation of night snoring and breath holding.

Snoring, although annoying to others, is not inherently dangerous. However, about 10% of people who snore suffer from obstructive sleep apnea (OSA), which can lead to extremely unpleasant consequences. This cause of poor sleep is manifested by short-term cessations of breathing, in severe forms there can be up to 400-500 per night. This leads to an acute chronic lack of oxygen during sleep, which increases the risk of developing various diseases. First of all, the brain suffers.

Each cessation of breathing is accompanied by a partial or complete awakening of the brain, due to which the quality of sleep deteriorates sharply. In the mornings, people who are familiar with this cause of sleep disturbance, OSAS are worried about headache and fatigue. Moreover, according to statistics, people with OSAS are more likely to have car accidents because they tend to lose concentration and even fall asleep while driving.

Where to go: with This cause of poor sleep in adults should first contact a therapist. He will ask clarifying questions, give general recommendations and refer you to a specialized doctor.


What gives it away: with this cause of poor sleep in the morning, things are out of place, there are difficulties with concentration, mood disorder.

What happens while you sleep : In this sleep disorder there are active actions in the dream.

Often referred to as sleepwalking, this cause of sleep disturbance is quite rare in adults (1-3% of the population). People with this diagnosis perform active actions in their sleep: sit down, stand up or walk around the room. In some cases, they try to clean up, rearrange things.

The cause of sleep disturbance becomes dangerous if a person tries to cook food, leave the house, drive. Despite the fact that all actions are performed during sleep, the eyes remain open, although the gaze is clouded and dispersed. Stress, high body temperature, sleep disturbance, genetic predisposition can provoke walking in a dream.

Where to go: In order to confirm or refute this cause of poor sleep, it is necessary to undergo a polysomnographic study. It is carried out by a somnologist.

Restless legs syndrome

What gives it away: this cause of sleep disturbance provokes discomfort in the legs in the morning

What happens while you sleep: in this cause of sleep disturbance, involuntary movements of the legs occur

sensations in the legs cause discomfort and significantly reduce the quality of night rest. Modern research shows that this cause of bad sleep in adults occurs in 2-10% of the population, regardless of age and gender. It is this syndrome that causes about 15% of cases of chronic insomnia.

Moderate exercise during the day, a balanced diet, and a warm foot bath before bed can help in some cases to help manage the cause of poor sleep. But it’s still worth talking to a doctor so that he can help identify the causes of the syndrome. This way you can make sure that the problem does not become chronic and does not recur during a period of stress.

Where to go: with this cause of sleep disturbance, you should contact a therapist or neurologist. The specialist will find out the nature of the disease and send you for additional examinations.

Other causes of sleep disturbance

There are several other conditions that affect the quality of sleep and make us feel tired and overwhelmed immediately after waking up. Here is a short list of possible causes of poor sleep in adults, in addition to those already listed above:

  • Accumulation of adenosine in the brain - we spend the last few hours before waking up in REM sleep. Just at this time, our brain consumes a large amount of adenosine triphosphate - a source and carrier of energy in cells. It also suppresses vigor and attentiveness, which is why we suffer from the causes of sleep disturbance and often wake up already tired;

  • Co-sleeping — sharing a bed with someone can also cause poor sleep. Basically, this problem is close to women - the presence of someone else in bed either does not affect men's sleep at all, or even makes it only better. If your sleep with a partner is also preceded by sex, then your chance to wake up after this sleepy, alas, only doubles;

  • Going to bed late - if you have a habit of going to bed late, then the quality of sleep in this case is likely to suffer;

  • Lack of sugar - scientists have proven that eating sweets before bed can have a positive effect on well-being in the morning. Therefore, the cause of poor sleep at night can be a banal lack of sugar;

  • Drinking alcohol before bed - yes, alcoholic drinks can really relax and help you fall asleep faster. But the quality of sleep will suffer. The cause of poor sleep in adults in this case is alcohol, which suppresses the natural rhythms of brain activity and affects the fast phase of sleep. The result is that sleep becomes interrupted and short, which is why we wake up completely broken in the morning.

How to treat sleep disorders

If you have long been tormented by the question of why I do not get enough sleep, then the problem cannot be ignored - it must be solved. With this serious problem, you can turn to doctors - it is better to start with an appointment with a psychotherapist and a neurologist.

When the cause of poor sleep is difficult to determine, doctors may refer the patient to a sleep specialist called a somnologist. After finding out the underlying cause and conducting a series of tests, a person may be prescribed sleeping pills that will help normalize sleep.

How to deal with sleep problems on your own

There are a few tips to help you deal with your sleep problems on your own. By following these recommendations, you have every chance to significantly improve the quality of sleep, which will help you get up in the morning cheerful and full of energy and strength.

Here are some useful tips:

  • try to go to bed at the same time - this will help you set your biological clock;
  • create for yourself all the conditions for a comfortable rest: make clean linen, air out the bedroom before going to bed, turn on the aroma lamp;
  • take a warm shower before going to bed;
  • give up heavy meals 2 hours before bedtime, but at the same time you should not go to bed hungry either;
  • Before going to bed, drink a glass of warm milk with honey or a cup of soothing tea;
  • avoid coffee, alcohol and smoking just before bedtime;
  • before going to sleep try not to do things that can overexcite your nervous system;
  • ask someone close to give you a light relaxing massage.

how to get enough sleep and how to calculate your sleep rate

A lot has been said about the importance of sleep: if you don't get enough sleep regularly, you can get a bunch of health problems. Due to lack of sleep, immunity drops, chronic diseases worsen, and in general, health fails. But there is no universal norm of sleep that is suitable for absolutely everyone - there is only an approximate duration.


Ilya Belov



Sleep problems

Figured out how to understand how much sleep you need specifically, when to get up and when to go to bed to get enough sleep.

Do not self-medicate! In our articles, we collect the latest scientific data and the opinions of authoritative health experts. But remember: only a doctor can diagnose and prescribe treatment.

How much sleep do you need?

Sleep duration is influenced by many factors. One of them is age. It is clear that babies need much more sleep than adults. And here are the sleep norms recommended by experts for people of different ages:

  • children under 4 months old - from 17 to 23 hours, including daytime sleep;
  • children under one year old - from 12 to 16 hours, including daytime sleep;
  • children aged 1 to 2 years - 11-14 hours including naps;
  • children aged 3 to 5 - 10-13 hours including naps;
  • children from 6 to 12 years old - 9-12 hours;
  • adolescents aged 13 to 18 - 8-10 hours;
  • adults - at least 7 hours.

An adult should not sleep more than 9 hours, health experts say. The fact is that too much sleep can be harmful to health, increasing, for example, the risk of developing Alzheimer's disease and the likelihood of heart problems.

How do you know if you're not getting enough sleep?


In addition to the very obvious options, when you have to sleep 3-4 hours at night, which is definitely not enough for a full recovery, to understand that you do not have enough sleep, ask yourself a few questions. This recommendation is made by the US Centers for Disease Control and Prevention (CDC). Here's what you need to understand:

  • Do you feel rested after 7 hours of sleep or you need at least 8 or 9?
  • Do you feel sleepy during the day?
  • Do you need coffee or other sources of caffeine (eg energy drinks) to feel alert?
  • If you sleep with someone in the same bed, have they noticed that you sleep restlessly, tossing and turning?

If, based on the results of the answers, you understand that that amount of sleep is not enough for you, you should think about how exactly you can change your regimen by increasing the duration of sleep.

Signs of chronic sleep deprivation to watch out for:

  • you are sleeping on the go;
  • you are more irritable than before;
  • you are less productive and less able to concentrate on tasks;
  • you eat more;
  • you make strange decisions for yourself;
  • skin looks dull.

You can sleep poorly not only because you go to bed late and get up early. Other disturbances can also affect the quality of sleep and its duration. For example, insomnia, chronic pain, obstructive sleep apnea, in which a person snores and stops breathing for a short time. If you notice that there are problems with your sleep and suspect that the reason lies in one of these conditions, then do not hesitate and consult a doctor.

What happens during sleep?

Our whole night's sleep can be divided into several cycles, each of which consists of successive stages - there are five in total.

  • Period between sleep and wakefulness.
  • The period when you fall asleep and are no longer aware of what is happening around you. The body temperature drops slightly, and breathing and pulse become uniform.
  • The longest and most recovery period, including two phases, when breathing and pulse slow down, pressure decreases, muscles relax. This is the period when the body is renewed and gains energy.
  • REM sleep, which accounts for about a quarter of a total night's sleep. During this period, brain activity is maximum, and this is exactly the time when we dream.

The ideal option is to wake up not in the middle of the cycle, but after it ends. Each cycle takes approximately 90 minutes (an hour and a half). This means that it is better if the duration of a night's sleep is 5 or 6 full cycles - 7.5-9 hours.

Sleep calculator

Especially for those who would like to improve their sleep and wake up refreshed, we have calculated the best time to go to bed and get up. We estimate that the sleep time will correspond to 5 or 6 complete sleep cycles, and it will take no more than 15 minutes to fall asleep.

Each line below lists wake up time - bedtime (assuming you sleep 5 cycles) - bedtime (if you plan to sleep 6 cycles) in sequence.

4:00 - 20:15 - 18:45

4:30 - 20:45 - 19:15

5:00 - 21:15 - 19:45

5:30 - 21:45 - 20:15

5:45 - 22:00 - 20:30

6:00 - 22:15 -20:45

6:15 - 22:30 - 21:00

6:30 - 22:45 - 21:15

6:45 - 23:00 - 21:30

7:00 - 23 :15 - 21:45

7:15 - 23:30 - 22:00

7:30 - 23:45 - 22:15

7:45 - 00:00 - 22:30

8:00 - 00:15 - 22:45

8:15 - 00:30 - 23:00

8:30 - 00:45 - 23:15

8:45 - 1:00 - 23:30

9:00 — 1:15 — 23:45

Try going to bed and waking up according to your sleep cycle for at least a week, during which time you will be able to understand exactly how much sleep you need.

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