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How Long Is Each Sleep Cycle

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Sleep Stages Within The Sleep Cycle: A Breakdown

Each of the four sleep stages has a distinct purpose, sparking unique brain activity. As we move through the stages, our breathing slows down, our muscles begin to relax and our heartbeat slows all of this helps to recharge our mind and body as we sleep. Even though the brain remains hard at work during sleep, it is restorative labor!

Sleep stages

Table credit:Sleep Foundation

Our understanding of sleep stages keeps evolving:Prior to 2007, many sleep experts referred to five sleep stages. After a study was released by the American Academy of Sleep Medicine , the majority consensus was updated to confirm that there are four sleep stages within a sleep cycle.  

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, its likely that the light, deep, and REM ratio is exactly where it should be in young people.

If theyre 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.

How Much Sleep Do We Need

The amount of sleep each person needs depends on many factors, including age. Infants generally require about 16 hours a day, while teenagers need about 9 hours on average. For most adults, 7 to 8 hours a night appears to be the best amount of sleep, although some people may need as few as 5 hours or as many as 10 hours of sleep each day.Women in the first 3 months of pregnancy often need several more hours of sleep than usual. 

People tend to sleep more lightly and for shorter time spans as they get older, although they generally need about the same amount of sleep as they needed in early adulthood. About half of all people over 65 have frequent sleeping problems, such as insomnia, and deep sleep stages in many elderly people often become very short or stop completely. This change may be a normal part of aging, or it may result from medical problems that are common in elderly people and from the medications and other treatments for those problems

The amount of sleep a person needs also increases if he or she has been deprived of sleep in previous days. Getting too little sleep creates a sleep debt, which is much like being overdrawn at a bank. Eventually, your body will demand that the debt be repaid. We dont seem to adapt to getting less sleep than we need; while we may get used to a sleep-depriving schedule, our judgment, reaction time, and other functions are still impaired.

Why Is Sleep Important For Our Health

Sleep and sleep-related problems play a role in a large number of human disorders and affect almost every field of medicine. For example, problems like stroke and asthma attacks tend to occur more frequently during the night and early morning, perhaps due to changes in hormones, heart rate, and other characteristics associated with sleep. Sleep also affects some kinds of epilepsy in complex ways. REM sleep seems to help prevent seizures that begin in one part of the brain from spreading to other brain regions, while deep sleep may promote the spread of these seizures. Sleep deprivation also triggers seizures in people with some types of epilepsy.

How Much Rem Sleep Should You Get


Although theres 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 dont go making sudden changes in your sleep habits it is not clear which is the cause and which is the effect.

Stages Of Sleep: Rem And Non

Take-home Messages
  • There are five different stages of sleep including both REM and NREM sleep. The five stages make one sleep cycle which usually repeat every 90 to 110 minutes.
  • Stage 1 non-REM sleep marks the transition from wakefulness to sleep. This stagetypically lasts less than 10 minutes and is marked by a slowing of your heartbeat, breathing, and eye movements , as well as the relaxation of your muscles.
  • Stage 2 non-REM sleep is a period of light sleep before you enter deeper sleep, lasts roughly 20 minutes. Stage two is characterized by further slowing of both the heartbeat and breathing, and the brain begins to produce bursts of rapid, rhythmic brain wave activity known as sleep spindles.
  • Formerly known as stages 3 and 4, stage 3 is the final stage of non-REM sleep. This is the deepest period of sleep and lasts 20 to 40 minutes. Your heartbeat and breathing slow to their lowest levels, and your muscles are so relaxed that it may be hard to awaken you.
  • REM sleep occurs 90 minutes after sleep onset, and is a much deeper sleep than any of the three stages of non-REM sleep. REM sleep is defined by rapid eye movements and an almost complete paralysis of the body, and a tendency to dream.

Put simply, sleep is a state of perceptual disengagement from and unresponsiveness to the environment, marked by unique physiological and behavioral processes .

  Table of contents

What Goes On During The Sleep Cycle

Falling asleep isnt as simple as just closing your eyes and heading straight to dreamland. In fact, your brain and body go through various stages of Rapid Eye Movement and Non-REM sleep that differ according to how deep and restful they are. The sleep cycle is basically made up of four such stages and spans about 1.5 to 2 hours, so you typically go through several cycles throughout a standard night’s sleep. Heres a breakdown of what happens in each cycle.

What happens during NREM Stage 1?

This stage occurs when you are just falling asleep. At this stage, your sleep is light and easily disturbed by external influences. While your body is starting to relax into sleep and your brain activity slows down, some people may experience hypnic jerks or feel a free-falling sensation that jolts them back awake.

What happens during NREM Stage 2?

Once you have gotten past stage 1, your heart rate will begin to slow even more and your core body temperature drops, bringing you to stage 2 of NREM sleep. You are experiencing a deeper sleep than before, and it will be harder to wake you up. This stage is usually the longest in the sleep cycle, making up almost half the entire sleep cycle.

What happens during NREM Stage 3?

What happens during REM?

Photo: Active Health

How Well Are You Sleeping At Night

When we dont achieve good sleep regularly, including REM sleep, we can feel the effects, especially in our ability to focus, think, and retain information. The different sleep stages likely work together and complement each other. We need all of them for proper processing during sleep.

If you are constantly tired during the day, if you are feeling moody or irritable, or if you are struggling to focus, its possible that your sleep stages are being disrupted, by frequent arousals or other reasons, and as a result, the quality of the sleep you are getting suffers. It is important to consult a physician if you suspect a sleep disorder. A sleep tracking app can also monitor your sleep and help you determine if your sleep cycles are being disrupted. 

When Should I Set My Alarm

When Should I Set my Alarm?

An individual sleep cycle typically lasts around ninety minutes to two hours, during which the brain cycles from slow-wave sleep to REM sleep. However, the sleep cycle is not as simple as cycling through the stages sequentially.

As the night progresses, the amount of time we spend in a specific stage changes, as does the order of the stages. For example, the average length of the first non-REM-REM sleep cycle is 70 to 100 minutes.

The second, and subsequent, cycles are longer lasting â approximately 90 to 120 minutes . In adults, REM sleep increases as the night progresses and is longest in the last one-third of the time spent asleep. N2 begins to account for the majority of non-REM sleep, and N3 can even disappear altogether .

On the average night, adults typically need to complete at least four or five sleep cycles per night, or 7 to 9 total hours of sleep . However, there is a large degree of variability from person to person and from night to night .

Babies, for example, have shorter sleep cycles, lasting only about 50 minutes for the first nine months of life, and it is typical for newborns to sleep anywhere from 14 to 18 hours a day .

For naps, the most professionals agree that shorter naps are better if a personâs goal is to wake up feeling refreshed and alert. However, the results of a 2019 study indicated that 25-, 35-, and even 45-minute naps significantly reduced signs of stress and fatigue in physically active men .

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 wont 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 youve been having trouble sleeping or feel extra drowsy during the day, talk to your provider. There are many treatments available for sleep disorders.


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 and sleep apnea . Your provider can help you get the diagnosis and treatment you need.


Stages Of Sleep: A Guide To Nrem Deep & Rem Sleep Cycles

Sleep is something most of us just take for granted. And, unless were not getting enough sleep, its something we dont really think too much about.

But what actually happens when we sleep?

It might seem like our body just kind of shuts down and goes into rest and recovery mode, but the human body, and especially the brain, is wonderfully complex and more active than youre probably aware while sleeping.

This guide is going to give you a good understanding of:
  • the different stages of sleep and sleep cycles
  • what happens inside your brain while youre asleep, or dreaming
  • the bodys biological sleep mechanisms and circadian rhythm

What Happens During Non

There are three phases of non-REM sleep. Each stage can last from 5 to 15 minutes. You go through all three phases before reaching REM sleep.

Stage 1: Your are closed, but it’s easy to wake you up. This phase may last for 5 to 10 minutes.

Stage 2: You are in light sleep. Your heart rate slows and your body temperature drops. Your body is getting ready for deep sleep. This can last for 10-25 minutes.

Stages 3: This is the deep sleep stage. It’s harder to rouse you during this stage, and if someone woke you up, you would feel disoriented for a few minutes.

During the deep stages of NREM sleep, the body repairs and regrows tissues, builds bone and muscle, and strengthens the immune system.

As you get older, you sleep more lightly and get less deep sleep. Aging is also linked to shorter time spans of sleep, although studies show you still need as much sleep as when you were younger.

How Much Time Should You Spend In Each Sleep Stage

REM, Light, Deep: How Much of Each Stage of Sleep Are You ...

Below is a graphic depicting the average amount of time WHOOP members spend in each of the 4 stages of sleep on a nightly basis, as well as the percentage of total time each stage represents.


Its worth noting that for the most part our members are people who are interested in tracking their physiological data 24/7 and improving their overall performance, so its likely they make more of an effort to get quality sleep than the general population as a whole.

Every human body is different, and the amount of sleep we need varies from person to person. The middle 50% of all WHOOP members average the following per night:

  • 3:28-3:59 of light sleep
  • 1:44-2:00 of REM sleep
  • 1:23-1:32 of deep sleep
  • 0:43-0:50 awake

Get The Right Amount Of Sleep To Boostperformance + Positivity

Recent studies have proven that those who sleep well are more alert and have higher cognitive processing. They also noticed these positive symbols more often, leading to a more positive outlook. This can easily be translated to the workplace where communication and positivity are the key to a great work environment. This means that your most comfortable bed could be a key component to getting the job you want and creating the happy life you dream of. Dont let anxiety stop you from sleeping! Using a weighted blanket will help you fight insomnia caused due to anxiety.

What Influences The Quality And Length Of Sleep

Since sleep and wakefulness are influenced by different neurotransmitter signals in the brain, foods and medicines that change the balance of these signals affect whether we feel alert or drowsy and how well we sleep. Caffeinated drinks such as coffee, and drugs such as diet pills and decongestants stimulate some parts of the brain and can cause insomnia, or an inability to sleep. Many antidepressants suppress REM sleep. Heavy smokers often sleep very lightly and have reduced amounts of REM sleep. They also tend to wake up after 3 or 4 hours of sleep due to nicotine withdrawal. Many people who suffer from insomnia try to solve the problem with alcohol the so-called night cap. While alcohol does help people fall into light sleep, it also robs them of REM and the deeper, more restorative stages of sleep. Instead, it keeps them in the lighter stages of sleep, from which they can be awakened easily.

We lose some of the ability to regulate our body temperature during REM, so abnormally hot or cold temperatures in the environment can disrupt this stage of sleep. If our REM sleep is disrupted one night, our bodies dont follow the normal sleep cycle progression the next time we doze off. Instead, we often slip directly into REM sleep and go through extended periods of REM until we catch up on this stage of sleep.

Is There Meaning In Dreams

Some scientists believe that dreams are the cortexs attempt to find meaning in the random signals that it receives during REM sleep. The cortex is the part of the brain that interprets and organizes information from the environment during consciousness. It may be that, given random signals from the pons during REM sleep, the cortex tries to interpret these signals as well, creating a story out of fragmented brain activity.

Sleep Cycles Vs Sleep Stages Whats The Difference

A sleep cycle is the physiological process that we go through as we sleep. We dont sleep in one long phase, its much more complicated and interesting than that! Our total nightly sleep is made up of several sleep cycles. Each sleep cycle is typically classified into four sleep stages: N1, N2, deep sleep and REM sleep.

Not all sleep cycles during a nights sleep necessarily contain all four sleep stages. For instance, we have more deep sleep and less REM sleep at the beginning of the night. Towards the morning, we have more REM sleep, but usually very little or no deep sleep in these later sleep cycles. Having less disruption during each sleep stage contributes to higher quality, recuperative sleep.

The Power Of The Sleep Cycle

We often wonder why we are awake at night and worry over our sleep habits and patterns. To answer these questions, first we should come to understand the normal, natural state of the rhythms of sleep.

A person can get by on 6 or even 4.5 hours of sleep per day without question. The secret is NOT the amount of sleep, but rather the number itself; a multiple of 90 minutes will change your life.

1.5 hours / 3 hours / 4.5 hours / 6 hours / 7.5 hours

Those are the sleep quantities that you should aim to get, and those are what your body will naturally take, removing the alarm clock. Not always 100% of the time.

Go to sleep without an alarm clock, and watch what times you naturally wake up at. It will be a multiple of 90 minutes from when you first went to bed. This 90 minutes is known as a sleep cycle, and its how I live my life.

If there are drugs such as Ambien, Lunesta, Benadryl etc. on board these interrupt the bodys natural rhythms. In medical school we are forced to learn how to sleep on the run.

Typically, I sleep 3 hours a night, and nap for 90 minutes in the evening. Thats a total of 4.5 hours, and I am always alert, always awake and always feel rested and refreshed.

Oh, and on 3 hours of sleep a night, I have one cup of coffee at the most per day. The sleep cycle is a beautiful thing!

Studies show that the length of sleep is not what causes us to be refreshed upon waking. The key factor is the number of complete sleep cycles we enjoy.

Thalamus & Cerebral Cortex

The is the part of the brain, located near the center, that relays information received from our senses to the part of the brain that interprets and processes information from short to long-term memory the cerebral cortex.

The thalamus becomes relatively inactive during deep sleep, which is why we dont react easily to outside activity. Still, it is active during REM sleep, which is why the cerebral cortex is able to receive images and other stimuli from dreams.

Healthy Sleep Habits And How To Improve Your Sleep Cycles:

Everyone is different and the amount of sleep we need varies for each individual. Yet there are a few common factors that can help improve the quality of your sleep. Waking up several times during the night for a prolonged period of time will most likely result in achieving less of NREM stage 3 sleep, that is, deep sleep. 

Over time this can affect your sleep quality and cause sleepiness and lack of focus during the day. Keeping a diary to note whether external factors, such as alcohol, caffeine intake, or stress contribute to a restless nights sleep can be helpful for you to understand what steps you can take to improve your sleep. Making sure your bedroom is dark and cool and developing a routine that helps you wind down before bedtime can also lead to a better nights sleep. 

Sleep and the quality of our sleep are fundamental to our well-being. Sleep cycles, and the sleep stages within them, are the reason we can take on each new day. So stay calm and carry on sleeping.  

Where Can I Get More Information

Alternative Sleep Cycles: 7

For information on other neurological disorders or research programs funded by the National Institute of Neurological Disorders and Stroke, contact the Institute’s Brain Resources and Information Network at:

Office of Communications and Public LiaisonNational Institute of Neurological Disorders and StrokeNational Institutes of HealthBethesda, MD 20892 Publication No. 17-3440c

health-related material is provided for information purposes only and does not necessarily represent endorsement by or an official position of the National Institute of Neurological Disorders and Stroke or any other Federal agency. Advice on the treatment or care of an individual patient should be obtained through consultation with a physician who has examined that patient or is familiar with that patient’s medical history.

All NINDS-prepared information is in the public domain and may be freely copied. Credit to the or the is appreciated.

What Are The Stages Of Sleep And Average Sleep Time For Each

There are 4 stages of sleep that your body experiences each night : Light sleep, deep sleep , REM sleep and awake. For a more in-depth explanation of how this works, check out Understanding Sleep Cycles and the Stages of Sleep.

Below well give a brief overview of the 4 sleep stages, then break down whats normal for how much time you should be spending in all of them.

How Do You Measure Sleep

For centuries people believed sleep to be a passive event, but in 1953, through the use of Electroencephalography machines, scientists Nathaniel Kleitman and Eugene Aserinksy were able to determine that the body passes through several complex stages of sleep.

EEGs record electrical brain activity. With electrodes placed on certain parts of the scalp, this noninvasive method is often used to measure wave patterns in the brain while participants are sleeping.


In this setting, the EEG is placed on the sleeper and monitored by scientist and medical professionals during a Polysomnography, better known as a sleep study. This is done to better understand sleep patterns and diagnose potential sleeping disorders.

Two Main Types Of Sleep

Further studies that measured eye movement and muscle activity along with brain activity resulted in the discovery of two types of sleep Non-rapid eye movement sleep and rapid eye movement sleep.

NREM sleep can be broken down into three distinct stages and are characterized by the slowing down and synchronization of brainwaves.

During stage 3, the deepest sleep, brain waves are very large and slow .

During REM, or active sleep, brain waves are small and fast . This stage of sleep is also accompanied by the eye movement that gives this sleep stage its name. This is also the stage associated the most with dreaming, which we will get to a bit further on.

What Is The Rem Sleep Stage And Why Is It Important

During REM sleep, the fourth stage in the sleep cycle, brain activity accelerates, and our body experiences muscle atonia- a temporary paralysis. Although the eyes can sometimes be still, mainly the eyes can be seen moving rapidly beneath the eyelids with the occasional rapid muscle twitching. Though dreams can pop up during any sleep stage, REM sleep is when we experience our most wild, vivid dreams.   

REM is thought to be important for emotions and motor-sensory functions. During REM sleep, the brain performs essential tasks: putting memories in their place, and enhancing cognitive functions. Think of sleep as a quiet time when our brain can finally get some housekeeping done.  

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