Sleep Stages

Understanding Sleep Stages and How Snoring Affects Them

If you are a snorer then you have likely heard and read countless times that it affects your sleep quality, which ultimately has an effect on your health.

Snoring StudiesLearning about sleep stages will help you understand why it’s important to find a product that will help you stop snoring. If your snoring is nasal-based, a nasal dilator may work best.

If you snore loudly while sleeping on the back, a Tongue Retaining Device could work best. Otherwise, a comfortable and successful way to stop snoring is by using a Zyppah or SnoreRx.

What is Sleep?

Of course you know sleep is something you do every night, but what is its purpose? The study of sleep is actually fairly new, which is also why case studies associated with snoring and sleep quality are also pretty current.

In the 1950s, Eugene Aserinsky, a graduate student, used a tool called an electroencephalograph to discover rapid eye movement sleep. Until this point, sleep was thought of as just a dormant position of the day.

We now know that sleep is a phase of the natural body cycle, which is based on a 24-hour period. There are several stages of sleep, and each one has its own characteristics and purposes. In uninterrupted sleep (aka non-snoring sleep), the body flows between the stages to complete 90- to 110-minute cycles all night. This is not the case with snorers.

The rhythm of sleep is known as the ultradian sleep cycle, and it consists of both rapid eye movement (REM) and non-rapid eye movement (NREM) stages. Every stage has specific physiological functions.

The average non-snorer gets about two full hours of sleep per night in the deepest sleep stage, but this isn’t the case for snorers. Unfortunately, you need to cycle through all sleep stages continuously for your body to fully recharge. As you learn more about these stages, you will understand why you are so tired in the morning, even after eight hours of sleep.

You’ll also understand why snoring makes it hard to lose weight and why it is so often associated with obesity. Of course, like sleep deprivation, carrying around extra pounds also takes a toll on your health.

Quality of sleep gets divided into two categories. First is subjective sleep quality, and it is the feeling you get from being well-rested after a good night’s sleep. The second is objective quality of sleep.

This is the more scientific variety, and it is determined by professionals by measuring time spent in different sleep phases. The two main contributing factors to results include the number of times a person wakes up throughout the night and the length of time spent in deep sleep stages.

Sleep Stages

As you are falling asleep, the activity in your body slows down. The small and fast beta waves produced by your brain slow and transition into alpha waves. It is common to experience hypnagogic hallucinations and vivid sensation during this phase, such as feeling like you are falling or believing that you hear someone call your name.

The myoclonic jerk is a common event, which you have probably experienced at some point. Your heart rate, breathing rate, and body temperatures all decrease.

Sleep Stages

Stage 1

Also known as NREM, N1, or simply “dozing off stages” is where you experience somnolence, or drowsy sleep. This is the transitional phase. Your brain’s alpha waves turn to theta waves, eyes roll slowly, and muscle tone starts to decrease. Although your body has started to relax, it is unlikely that your facial and throat muscles have relaxed to the point where you are snoring yet. The first phase lasts 5 to 10 minutes.

sleep-stage-2Stage 2

Brain waves begin showing signs of sleep in the NREM2 stage. The brain produces bursts of activity called sleep spindles that are undeniably recognizable on an EEG. If you ever go to a sleep specialist and look at the report of your sleep brain waves, you will easily be able to spot these spindles, as they look like mini earthquakes on the EEG.

In this stage all the muscles in your body fully relax. This is where your tongue collapses into your throat and causes the obstruction that result in your snoring. The average non-snoring adult spends about half their sleeping time in this second stage. Unfortunately, snorers spend a lot more time here than they should.

If your body has to work extra hard just to get oxygen all night, it is not going to let you move onto the next stage. Not to mention, if you are experiencing any apneas, your brain is waking you up to breathe. So, you drop back down to the first stage to start the cycle again.

Not to mention, if you have a partner who gives you an elbow to the ribs or tells you to roll over when you start snoring loud, they have just interrupted your cycle, too. Either way, you could spend the vast majority of the night going back and forth between these two stages.

Sadly, your body does not start to repair and recharge itself until you reach the next stage. Right about now, you probably have an “Aha!” moment, realizing why you need a pot of coffee to get going in the morning.

Stage 3

During NREM3, delta waves emerge, which are very slow brain waves. This is is the transitional period into the deepest sleep stage. Slow wave sleep is suggested to be the most restful stage. This is a restorative period.

There is an increase in blood supply to your muscles and tissue growth and repair take place. Energy is restored and hormones are released that are responsible for growth and development. This is also the stage where parasomnias occur, such as sleep walking, night terrors, Somniloquy, and nocturnal enuresis.

REM Sleep
Less REM sleep needed as aging


During an uninterrupted sleep cycle, you should reach the fourth stage in about 90 minutes. You only stay in it a short time, but the time lengthens with each cycle.

If you are constantly being awaken throughout the night because of your snoring then you are rarely going to spend an adequate amount of time in this stage. You may also be interested to know that the brain consumes more oxygen during this time than when you are awake.

So, if you have an obstruction causing snoring and decreasing your oxygen supply, there is little chance the brain is getting the oxygen it needs, unless it is stealing from other body components.

During REM sleep, your eyes dart back and forth. Muscles are turned off and energy is generated for the brain and body. This is the phase where most calories are burned.

This stage contributes to a healthy immune system. It also helps regulate leptin and ghrelin, two hormones that control your appetite by providing feelings of fullness when you eat. This is the reason why sleep deprivation leads to weight gain; you overeat because your body is full.

REM is also known as the dream stage because this is where the most vivid dreams occur. Despite it being an extremely deep sleep phase you experience paradoxical sleep. Your body is sleeping, but your brain is very alert. This is why you commonly wake up while having a vivid dream.

Sleep and Health

Now, you know snoring is robbing you of sleep; it’s time to learn just how damaging low quality sleep really is. Sleep debt causes emotional, mental, and physical footage.

Mentally, you are at risk for cognitive impairment, memory loss, impaired moral judgement, ADHD-like symptoms, severe yawning, and poor concentration.

Sleep loss slows wound healing. Studies suggest that sleep deprivation decreases white blood cell count, which makes it harder for the immune system to control cancers.

Since your heart never slows to the point where it should be during deep sleep stages, you are at increased risk for heart disease, high blood pressure, heart attack, and stroke. Poor sleep quality is also associated with type 2 diabetes, tremors, aches, decreased reaction time, growth suppression, headaches, hand tremors, fibromyalgia, seizures, and risk of obesity.

Of course, in addition to the health concerns listed above, obesity also increases your risk for gall bladder disease, gout, osteoarthritis, sleep apnea, asthma, high cholesterol, metabolic syndrome, obesity hypoventilation syndrome, and reproductive problems.


  • What is the most important phase of sleep?

    The phase of sleep most commonly viewed as the most important is the fourth and last stage, otherwise known as rapid eye movement (REM) sleep. This phase generally occurs approximately 90 minutes after the person falls asleep. It is during this phase of sleep that dreams occur. However, most importantly, it is also associated with crucial mental, intellectual development. 

    During REM sleep, areas of the brain associated with learning and emotions are active, and information obtained and memories made throughout the day are processed and consolidated. Some of these structures include the hypothalamus, thalamus, cerebral cortex, and pons.

    If you’re waking up feeling groggy, cranky, tired, this is likely either because you have woken up in the middle of an interrupted REM sleep phase, or because you are chronically deprived of sufficient REM sleep. On the flip side, sufficient REM sleep is what makes people feel well rested and refreshed when they wake up. Getting enough REM sleep is crucial to having the energy and focus to function throughout the day.

  • What is a normal sleep cycle?

    The sleep cycle is typically broken up into four stages: three stages of non-REM sleep and one final stage of REM. Stage 1 typically lasts no more than several minutes long – the average is about 14 minutes. Stage 2, light non-REM sleep, is the longest phase. Stage 3 is deep sleep, or “slow wave sleep”. The final, fourth stage is REM sleep, which first occurs about 90 minutes into the sleep cycle and is associated with greater brain activity. Snoring typically occurs in the last two stages. 

    After the REM stage, the cycle begins again with stage 2, and the brain activity begins to slow back down into deep sleep in stage three. 

  • What are the different stages of sleep?

    Stage 1 is the relatively brief transition period between being awake and falling asleep. It usually lasts a few minutes. During this transition, the body’s muscles begin to relax, breathing rate begins to drop and even out, and brain waves begin to slow. The alpha and beta brain waves that occur during wakefulness transition into theta waves, which are slower and have greater amplitude. 

    Stage 2 is the next stage of non-REM sleep. It is still categorized as light sleep. During this phase, the theta brain waves continue to slow down but are now occasionally punctuated with structures called sleep spindles and K-complexes. Sleep spindles are short segments in brain wave activity that have a higher frequency, while K-complexes have a higher amplitude. The muscles continue to relax, heart rate continues to slow, and body temperature continues to drop.

    Stage 3 is the period of non-REM deep sleep. Heart rate and body temperatures reach their lowest points. Brain activity waves at this point are now at their lowest frequency and highest amplitude and are now called “delta waves.” Interestingly enough, although muscles are typically now very relaxed, they are still able to move. Individuals who tend to sleepwalk do so in this phase of sleep.

    The final stage is REM sleep. As its name suggests, the eyes begin to move side-to-side. During this stage, muscles in the limbs become paralyzed to prevent injuries that might occur from physically reacting to vivid dreams. 

  • What is the deepest stage of sleep?

    The deepest stage of sleep is Stage 3, which is also referred to as slow wave sleep or SWS. In this stage, there is little or no eye movement. It is the most difficult phase of sleep to be woken up from. The brain activity waves generated by EEG measurements during this phase are known as delta waves – they are the slowest and biggest waves. 

    The deep sleep phase is necessary for the body’s physical repairing processes. Important functions such as liver detoxification, kidney filtration, muscle tissue repair, and cell replacement occur during this time. The first sleep cycle usually has longer periods of deep sleep. Each subsequent cycle, the brain spends less time in deep non-REM sleep, and more time in REM sleep. 

  • Is it good to have light sleep?

    According to the research we have so far, light sleep does not contribute any major physical or cognitive functions or mechanisms. In other words, there are no recommended minimum hours of light sleep required for each night. Deep sleep and REM sleep are generally understood to be more critical. 

    However, light sleep is not “bad.” Although not as important as the other phases, it is still restful and refreshing and serves as a practical and necessary transition period between wakefulness, deep sleep, and REM sleep phases. It’s not possible for the brain and the body to safely jump from the high-frequency, high-energy brain activity of wakefulness to the low-frequency brain activity of deep sleep, or vice versa. 

  • How many hours of deep sleep do you need?

    The number of hours of deep sleep needed depends on the person and the situation. Generally, the longer one has been awake, the more hours of deep sleep their body will need to repair fully and for the individual to feel fully rested. 

    However, the exact number of hours still varies significantly from person to person because of complex factors like age and genetics. The older a person gets, the less deep sleep they need. Younger children need more deep sleep because it is a crucial period for physical growth and development. 

    On average, it is recommended that adults 18 years and older try to get about 1.5-2 hours of deep sleep every night. Because deep sleep is usually around 20% of sleeping time, this requires about 8 hours of sleep per night. 

    Chronic sleep deprivation has been associated with shorter life expectancy, a host of health problems, and significantly lowered levels of cognitive function. It’s simply not possible to function at your best if you’re not getting the sleep you need. Additionally, there are serious, long-term health consequences so complex they are still not fully understood. 

  • What is a normal sleep pattern?

    A normal night of sleep consists of cycles that rotate throughout the different stages. If the person is getting the full, recommended 8 hours of sleep per night, a full night usually has about five cycles. 

    In the first cycle of sleep, the individual begins with Stage 1, then quickly moves to Stage 2, then Stage 3. Stage 3 is the longest in the first cycle of sleep. After the first iteration of Stage 3, you spend a brief amount of time in Stage 2 in transition to REM sleep. The REM stage in the first sleep cycle is the shortest. 

    As the night progresses, the brain alternates between Stages 1 (very little), 2, 3, and REM. Less time is spent in Stage 3, and more time is spent in Stage 2 and REM. Stage 1 might never occur after falling asleep until sunrise, or only if the person is disturbed. Additionally, older people spend more time in Stage 2 of sleep. The end of a REM phase marks the end of each cycle of sleep. 

    The exact pattern or amount of time spent in each cycle varies from night to night and from person to person. Generally, light sleep serves as transitions between the high-activity of wakefulness and REM, and the low-activity of deep sleep.

    It is considered ideal to wake up at the end of a REM phase, or the end of a sleep cycle. At the point, the person is most easily woken up and feels the most refreshed and well rested. 

  • What is stage 3 of sleep?

    Stage 3 of sleep is known by many names such as deep sleep, slow wave sleep (SWS), and N3. Sleep researchers used to break this stage of sleep up into two separate stages. Using this method of categorization, there were 2 stages of light sleep, 2 stages of deep sleep, and one final, fifth stage of REM sleep. But more recently, the two deep sleep categories have been consolidated into just Stage 3 or N3. 

  • What is the paradoxical sleep?

    Paradoxical sleep is another name for REM sleep, which is the fourth stage of sleep that occurs at the end of each sleep cycle. It acquired its name from the fact that a person in REM sleep, because of their paralyzed muscle limbs, appears to be in deep sleep. However, during REM sleep, the person’s eyes underneath their closed lids are actually moving side to side in a rapid manner. Additionally, their brain wave activity is very high, and breathing might be very rapid. REM sleep is also associated with the most vivid dreaming. 

  • What is the cause of heavy sleeping?

    The longer a person has been awake or, the more physically exhausted they are, the more time they will spend in heavy, deep sleep during their sleep cycles. 

    If you’re trying to fall asleep faster or stay asleep longer, try getting more, regular exercise and avoiding caffeine and sugar in the late afternoons and evenings. Some people find it helpful to establish a set, relaxing routine right before bed. This might include a warm bath, listening to soothing music, lighting a candle, or reading a book. 

    It’s also a good idea to avoid doing anything other than sleeping in your bed. Make your bed strictly a place for sleeping instead of a study spot or a place to watch TV. In this way, your brain will associate being comfortably in bed with getting ready to fall asleep. 

The Bottom Line

Snoring is not just an obnoxious sound keeping your spouse, roommate, or children up at night. Every night that your body is robbed of its time in deep sleep stages, you are damaging your present- and long-term health.

This is probably pretty disturbing, if you know you have been snoring for many years. Fortunately, the solution very well may be simply finding an anti-snoring device that works for you. Both mandibular advancement devices (MADs) and tongue retaining devices (TRDs) work to keep your air passage clear all night.

This allows your mouth and throat to be in an “awake” position, so the body doesn’t have to fight to get the oxygen it needs. It also eliminates anyone waking you up, so you stop snoring.

You will know when you have found an oral appliance that works for you because you will wake up feeling well-rested and energized. You will begin to feel healthier inside, and you will enjoy the peace-of-mind that comes along with knowing you have decreased your risk for diseases and diminished mental health.

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One Comment

  1. An estimated 40% of the UK population snore, this could be disrupting your partners sleep as well as your own! There is such thing as Obstructive Sleep Apnoea, which occurs as a result of complete obstruction of the upper airway at night which can cause you to wake up from a deep sleep. This lends itself to poor sleep, daytime sleepiness, and the potential for accidents at work. Patients may have headaches, be irritable, and perform poorly at work – you must also contact the DVLA.

    A sleep cycle lasts about 90 minutes and during that time we move through five stages of sleep. There are many sleep calculator apps you can use to time these and alarm clocks which will get you up at the best times.

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