What are the different stages of sleep?
What are the 5 stages of sleep?
There’s more going on when you sleep than you might imagine. You go through 5 stages of sleep every night, and each one has an important part in keeping you healthy and setting you up for the day ahead.
The five stages of the sleep cycle
Have you noticed that you tend to only remember dreaming in the early morning, or that you often wake up for a few moments, several times a night? The patterns of your sleep are structured around the different types of sleep you experience throughout the night. You cycle through two main types of sleep each night: rapid eye movement (REM) and non-rapid eye movement (NREM) sleep. NREM sleep itself is made up of four stages, followed by REM sleep. These 5 stages make up one full sleep cycle, and you go through several cycles each night. So, what happens in each stage, and what are the stages of sleep for?
Stage 1: The twilight stage
Stage 1 of sleep is the first of four NREM stages and is best described as ‘dozing off’. Each stage is defined by changes in your brain waves, muscle tone and eye movements. In this stage, your brain is getting ready for falling asleep: slow brain waves increase and begin to replace the higher frequency waves associated with a wide-awake brain. Although you are falling asleep, you’re still conscious of your surroundings. Your muscles aren’t fully relaxed, and your breathing hasn’t slowed yet. Although this stage lasts 1-5 minutes in the first sleep cycle, you only spend about 5% of the night in stage 1. This is because you tend not to spend much more time in this stage later in the night. In the first cycle of the night, you move quickly from stage 1 to deeper sleep.
Stage 2: Light sleeping
As you fall deeper asleep, your temperature and heart rate drop, and your eyes stop moving. This is the first stage where you are no longer aware of your surroundings. Snoring often starts during the light sleep of stage 2 and can wake you up, especially as you’re still easy to wake in this stage. If you’re not woken up in stage 2 by snoring or other issues such as pain or discomfort, then you will move into the deeper stage 3 of sleep.
Stage 3: Getting deeper
In stage 3 of sleep, your brain activity takes on a special pattern, with short bursts of activity while overall activity slows. Your muscles relax further, and your breathing slows. Stage 2 and 3 sleep together can last 10 – 25 minutes during the first sleep cycle, but time spent in these stages increases with each cycle. This means you spend more time in stages 2 and 3 later in the night. Together they are sometimes referred to as NREM 3. In total, you will usually spend around half of your time asleep in these stages.
Stage 4 NREM: Deep sleep
Stage 4 is also known as deep sleep, and it is vital for restorative sleep: it is when your body repairs and grows. Experts believe that your immune system is strengthened in this stage too, and not getting enough deep sleep can be harmful to your health. Luckily, it is much harder to wake someone up in this phase.
Your brain activity changes during deep sleep too, marked by a low frequency type of brain wave called a delta wave, which is why this stage is sometimes called slow-wave-sleep or delta sleep. Research suggests that deep sleep contributes to memory, learning and decision making.
You spend around 25% of the night in stage 4, but most of this time is in the first half of the night. During the early sleep cycles, stage 4 deep sleep lasts for 20-40 minutes. Later in the night, you spend less time in stage 4, and more time in REM sleep instead.
Stage 5: REM sleep
The final stage of each sleep cycle is REM sleep. Now brain activity picks back up, to almost the same level as when you’re awake. Although dreams can occur in any sleep stage, dreams in NREM sleep are less common. You also have the most vivid dreams in REM sleep, when your brain is most active. Your body, however, remains still. This is because your muscles are temporarily paralysed, except for your eyes and the muscles that control breathing. Your eyes remain closed but move quickly in REM sleep, which is where this stage gets its name.
You enter REM sleep around 90 minutes after falling asleep. Throughout the night, you spend increasingly more time in REM sleep with each sleep cycle. This means that while the first time you enter REM sleep it lasts only a few minutes, by the end of the night you can spend around an hour in REM sleep. As a result, most of our vivid dreaming happens in the second half of the night. So if you’ve had a dream that felt like it lasted all night and wondered how long does dreaming last, the answer is probably about an hour!
Why do we sleep in stages?
Although experts are still unravelling the mysteries around why and how we sleep, we know that each sleep stage plays a role in keeping our minds and bodies healthy and helping you to wake up feeling refreshed. The 5 sleep stages allow your body and brain to recover and grow. If you don’t get enough deep and REM sleep, you can suffer the next day with problems thinking, low mood and daytime sleepiness.
Long term disruption to your sleep, for example due to trouble falling asleep, sleep apnoea or restless leg syndrome, can have a big impact on your health. People with sleep apnoea who are repeatedly woken during the early stages of sleep can struggle to move through the stages to deeper sleep.
How to encourage a better sleep
Although you don’t have full control over your sleep cycle, there are a few things you can do to get a better night’s sleep. Improving your sleeping schedule and habits can help to ensure you go through the normal 4-6 sleep cycles and spend enough time in each of the 5 stages of sleep. Going to bed at the same time each night and waking up at the same time can be difficult, especially if you struggle with pain that makes it hard for you to fall asleep. But it’s a good way to regulate your circadian rhythm and ensure you feel sleepy at bedtime.
Addressing your sleep environment can help you get the best night’s sleep possible too. This means ensuring that you’re sleeping on the best mattress for you, with supportive pillows and hygienic bedding. Investing in a comfortable adjustable bed is the most important factor in ensuring you get uninterrupted sleep. By supporting you in the right position, an adjustable bed can help you to sleep free from disturbance due to pain or discomfort, and progress normally through each sleep stage. Ensure you have enough space per person too, as another person tossing and turning can also disrupt your sleep.
Your bedroom temperature should be between 17 and 19°C, and the room should be completely dark. It’s also a good idea to keep work or daytime activities out of the bedroom if you can. This will help to cut down on clutter that can be stressful at bedtime and remind you of chores that need to be done. It also helps keep a strong association in your mind between your bedroom and sleep.
Certain conditions can also make it hard to sleep well. People with sleep apnoea are likely to spend less time in deep and REM sleep because the airway collapses that they experience occur in these deeper sleep stages. As well as medical devices such as CPAP machines, raising your head and torso while you sleep is an effective way to reduce these disturbances if you have sleep apnoea. Pillows are one way to achieve this, but they are prone to sinking down during the night, leaving you lying flat. Adjustable beds can raise the whole head of the bed, and other sections too depending on the type of bed base, so you can lie fully supported in a position that lets you sleep undisturbed.
Remember that if you often feel tired during the day or think you might have sleep apnoea or another condition such as chronic pain that’s affecting your sleep then it is important to talk to a doctor to get specific care.
Buy the right adjustable bed for you
To have restful sleep, you need to complete each phase of sleep. Disruption to this pattern results in daytime sleepiness and difficulty concentrating in the short term, and can have serious health consequences if it continues.
Your bed is vital for getting a good, restorative night’s sleep. If you often wake up feeling tired, then an uncomfortable bed could be making it difficult for you to spend enough time in each stage of sleep. Our supportive and comfortable adjustable beds are designed to help you fall asleep easily, progress normally through each sleep cycle and get a better night’s sleep. Discover how purchasing an adjustable bed can improve your sleep with our bed buying guide.