Scientists when studying human sleep confirmed that: when sleeping, parts of the body remain active and these activities occur unevenly at different times. By monitoring the body of a person when sleeping, it is found that the sleeping process of people is divided into certain stages, at each stage the body has its own specific activities.
Sleep cycles are divided into 5 stages. The stages of the sleep cycle occur orderly to form a cycle and this cycle is repeated throughout the sleep time since you close your eyes the night before to when you wake up the next morning. At each stage, the state of the brain and body will be different. This also explains why early sleep is not a condition for us to to be awake and energized. The more important thing is you need to wake up at the right time.
Understanding and adjusting the cycle of sleep is the secret helping you have a good night’s sleep and wake up refreshingly despite going to bed at any time.
What is the Sleep Cycle?
A sleep cycle is a progression through the various stages of Non-REM sleep (NREM – non-rapid eye movement sleep) to REM Sleep (rapid eye movement sleep) before beginning the progression again with Non-REM sleep. Typically, a person often begins a sleep cycle every 90-120 minutes resulting in four to 5 cycles per sleep time, or hours spent asleep.
One does not go straight from deep sleep to REM sleep, however. Rather, a sleep cycle progression through the stages of non-REM sleep from light to deep sleep, then reverse back from deep sleep to light sleep, ending with time in REM sleep before starting over in light sleep again.
What are the Stages of Sleep?
During your sleep, the body moves through five different stages of both REM (rapid eye movement) and NREM (Non-REM Sleep / non-rapid eye movement) sleep. Specifically, Non-REM sleep consists of a period of sleep deprivation, sleepiness, deep sleep, and very deep sleep. REM sleep only includes the dream period.
Read more: What’s the REM Sleep?
Read more: What’s the Non-REM Sleep”
Over the night’s sleep, the body will go through this five-stage cycle about 4 to 6 times, spending an average of 90 minutes in each stage.
Each stage of sleep cycle serves a unique restorative function, including muscle recovery, hormone regulation, and memory consolidation. Without a full night of sleep, your body and brain are physically and mentally deprived of the essential elements needed to help you capture the day.
5 Stages of the Sleep Cycle
Up to now, there are many posts on the internet that mention the sleep as well as advise how to get a good night’s sleep. It’s easy for us to find these posts with a subject such as: Tips for good night’s sleep; A Easy Strategy For Better Sleep In Less Time; Tips To Stay Awake After A Sleepless Night; How to wake up early in the morning?; Key to get heavy/deep sleep; How to sleep quickly within 1 minute;… Some posts also instruct how to cure insomnia by medicine or not.
Read more: Sleep Tips and Tricks
Actually, insomnia or other problems involved in sleep are showed through stages of the sleep cycle. The factors that interrupt or affect to the sleep cycle are the reason why make insomnia or other problems involved in sleep. Therefore, eliminating the bad factors that impact to the sleep cycle, at the same time creating good conditions for the body to sleep and wake up in natural biological time is the most effective method to sleep well and have good health.
Before applying the sleep cycle for solving the problems of sleep, we should study detail in body’s activities through stages of the sleep in a cycle.
Stage 1 – ‘Pre-sleep’ (lulling to sleep)
Normally, this stage only lasts from 3-15 min. This stage begins when you close your eyes to start sleeping. At this stage, your body changes gradually to the sleepy stage and can be awakened easily. If wake up at this stage, you usually remember unclear images, even some people can get convulsion suddenly, which is a reaction that feels like they are falling before.
This convulsion called hypnic myoclonia, occurs similarly another claps your shoulders which make startle you while you are concentrating your thought.
State 2 – Light sleep (or shallow sleep)
This stage accounts for about 50% of the total sleep time. At the stage of light sleep, your eyes will stop moving and your brain activity (brain wave) also becomes slower. Sometimes, inside the brain, the fast waves called sleep spindle, they will decrease gradually until the next stage.
State 3 – Deep sleep
This stage only accounts for less than 10% of the total sleep time. Deep sleep is the stage between light sleep and very deep sleep. At this period, the brain wave occurs very slowly and called delta wave, sometimes occurs the fast waves. The temperature, heart rate, breath, blood pressure are reduced, muscle and bone can be stretched.
State 4 – Very deep sleep stage
This stage accounts for about 20% of the total sleep time. It is an important period help body can totally rest. The temperature, heart rate, breath rate and blood pressure reduced to the lowest level, there is no movement of both your eyes and arms/legs. The waves that exist in the brain at that stage is the slow wave delta. People who awake this stage usually feel dizzy, lonely, disoriented, then the new brain activity can occur again a few minutes later.
State 5 – REM Sleep (Dreaming sleep)
This stage is called REM (rapid eye movement) which accounts for about 20% of the total sleep time. At this period, in spite of sleeping, the temperature, heart rate, breath rate and blood pressure both increase, eyeballs move fast while arms/legs no have movement. Dreams appear, for people who awake suddenly at the REM stage, they will recall stories that seem to be nonsense-dreams. At the end of the REM stage, normally your body will awake temporarily, then repeat the sleep cycle until morning.
Everything you should know about 5 states of sleep with this infographic:
How to calculate my sleep cycle?
Base on the knowledge about the States of the sleep cycle, we have a perfect wake-up time formula:
WAKE-UP TIME = BEDTIME + 1.5H X 5 + X
- 5h = 90 minutes: equivalent to 1 cycle of the sleep.
- 5h x 5: equivalent to the total 5 stages of a sleep cycle.
- X: Estimated time period from lying down to sleep til when the body enters stage 1.
Each person will have a different X value. If you don’t know how you can determine your X value, don’t worry. The scientists have already calculated an average figure. Each person usually takes about 14 minutes to go to sleep.
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How long is the sleep cycle?
Usually, a sleep cycle lasts around 90 to 110 minutes. In the first cycles, the duration of the Dream stage is relatively short, while the Deep Sleep and the Very Deep Sleep stages are longer. The closer to the morning, the time for Deep Sleep and Very Deep Sleep decrease and is replaced by the Dream stage.
Near the morning, the sleep cycle mainly consists of 03 stages: Pre-Sleep stage, Light sleep, and Dream. If your sleep time is 08 hours a night, the Pre-Sleep and Light Sleep stages take about 4 hours, Deep Sleep and Very Deep Sleep take about 2 hours and the Dream stage takes about 2 hours. This division varies according to the age and physiological characteristics of each person. Usually, adult sleep cycles are shorter and repeat more times than children. That’s why adults often wake up at midnight.
How does Sleep Cycle Change With Age
As we get older and undergo variety of physical changes, the Sleep Cycle (or sleep pattern) change as well. Most people find the age changing make them harder to not only fall asleep but also stay asleep. It is a common misconception that sleep needs decline with age.
Total sleep time stays the same or is slightly decreased (6.5 to 7 hours per night). It may be harder to fall asleep and you may spend more total time in bed. The transition between sleep and waking-up is often abrupt, which makes older people feel like they are a lighter sleeper than when they were younger.
Total sleep time actually stays constant or is slightly declined (6.5 to 7 hours per night). It may be harder to fall asleep and you may spend more total time in bed. For older people, their sleep are often be abrupted. They are easily be awakened (about 3 or 4 times each night) because of some sudden noise, nocturia, anxiety or the pain from long-term (chronic) illnesses, etc. which makes them seem to struggle with the night sleep.
Less time is spent in Non-REM sleep. They may feel tired, dizzy, deprived of sleep despite the total time on the bed is not changed.
These values are the average recommended hours of sleep for your age group:
|Average Sleep Hours by Age|
|Age||Hours Needed||Maybe appropriate|
|Newborn to 3 months old||14 – 17 hrs||11 – 19 hrs|
|4 to 11 months old||12 – 15 hrs||10 – 18 hrs|
|1 to 2 years old||11 – 14 hrs||9 – 16 hrs|
|3 to 5 years old||10 – 13 hrs||8 – 14 hrs|
|6 to 13 years old||9 – 11 hrs||7 – 12 hrs|
|14 to 17 years old||8 – 10 hrs||7 – 11 hrs|
|Young adults (18 to 25 years old)||7 – 9 hrs||6 – 11 hrs|
|Adults (26 to 64 years old)||7 – 9 hrs||6 – 10 hrs|
|Older adults (65+)||7 – 8 hrs||5 – 9 hrs|
|Source: National Sleep Foundation|
What is a good sleep?
“You can’t get what you want if you don’t know exactly what you want”.
You spend 8 hours every night to sleep. This is a good habit. However, when you wake up in the morning, you still feel tired and want to sleep again. Why? Because what you really need is a good sleep!
You will sleep well when you get enough recommended sleep time and sleep quality. The sleep cycles last for 90-110 minutes each, occur one after another and you don’t get awake in the middle of a cycle. In addition, your sleep is deeper and more quality if, in each sleep cycle, the duration of the Deep Sleep, Very Deep Sleep and Dreaming stages are prolonged.
How to have a good sleep?
Based on an understanding of Sleep Cycle, all we need to do to sleep well, sleep deeply, and get enough sleep is to follow the three optimal principles for sleep stages.
- Principle one: Reduce time for Pre-Sleep stage and Light Sleep stage.
- Principle two: Increase time for Deep Sleep and Very Deep Sleep stages.
- Principle three: Optimize positive Dream sleep time.
With these three principles, you may have come up with the most appropriate goals and plans for yourself. Below are some suggestions which are summarized from different sources. Hope you find them helpful for you.
Do not stay up too late. Staying up late delays your first sleep cycle. According to the natural biological rhythm, melatonin, sleep-regulating hormone, is released by the pineal gland in a certain period of time. At night, melatonin is released at the highest concentration with the aim of helping you sleep. The fact that you try to stay up late makes some sleep cycles ignored.
Do not sleep too early. According to the natural biological clock, your body sleeps at 9 pm (this is just an example, your circadian rhythm may be different) but you want to sleep early and try to sleep at 6 pm because of the need of waking up early in the morning. However, your early sleeping effort is useless. Trying to sleep earlier than the natural biological clock makes it difficult for you to sleep, the Pre-Sleep and Light Sleep stages are prolonged. What the body really needs in a night of sleep is Deep Sleep, Very Deep Sleep And Dream Sleep time.
Do not interrupt the sleep cycle. Even if you are falling deeply into sleep, a loud noise caused by a glass jar being broken in your house might wake you up. Unfortunately, you may be awakened when your body is in a Deep Sleep, Very Deep Sleep or Dream Sleep stage, interrupting your sleep cycle, which means you have to start another new cycle. Deep Sleep time is reduced as a consequence. Factors from outside environments such as cars, dogs barking, noise from refrigerator engines, etc. can undermine your deep sleep. So try to create a quiet sleeping environment and not be disturbed by anything.
Wake up at the end of the last sleep cycle. An alarm clock can ring when you are in Deep Sleep or Dream stage. This is obviously not good because it reduces your Deep Sleep and Dream time. Although you do not want the alarm clock to ring when you are deep asleep, you need to wake up to go to school or work on time. The good news is that this is completely possible.
But how to easily get What time is the end of the last sleep cycle? Don’t worry, try our Sleep Calculator here:
Very easy, simple and fast!
Build a bedtime routine and wake up at a certain time. Sunlight and natural biological clock are the most effective tools to help you wake up on time with a bright face, so you will have an effective day of study and work.
Dream stage is important, let’s have beautiful dreams. Whether you want it or not, dreams still take place every night in the cycles of sleep. Someone remembers the last night’s dream, some don’t. This is completely normal. Dream sleep helps the brain repair memory, help the body’s energy be restored. Sleep is a miracle. If you can have beautiful dreams, your spirit will be more cheerful and relaxed. To have good dreams, before you go to bed, let’s relax, forget the unpleasant things of the day, remember instead the good things that happened. When your thoughts are filled with joy, you will dream beautifully.