What is Deep Sleep or Slow-Wave Sleep?

We’ve all heard a lot of people talking about deep sleep (also known as slow-wave sleep) and how our bodies need a certain amount of nurturing sleep daily to function healthily. But have you ever wondered what exactly is deep sleep? If yes, we’ve got it all covered in this blog - everything from its incredible benefits to how you can improve your deep sleep. 

But not to worry, we’ve got your back! Here’s how you can encourage deep sleep with these 8 effective tips.

1. Say bye to distress with exercise: Exercising is very helpful in reducing anxiety and improving sleep habits.
2. Routine is key: Try waking up and going to sleep at the same time daily. Create a routine that works best for you and stick to it!
3. Caffeine before bed is a NO-NO: Stick to water or other decaffeinated drinks before bed…

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What is Deep Sleep or Slow-Wave Sleep?

We’ve all heard a lot of people talking about deep sleep (also known as slow-wave sleep) and how our bodies need a certain amount of nurturing sleep daily to function healthily. But have you ever wondered what exactly is deep sleep? If yes, we’ve got it all covered in this blog- everything from its incredible benefits to how you can improve your deep sleep. 

Deep sleep is the sleep stage that is directly connected to the slowest brain waves during sleep. Owing to how the EEG activity is synchronized, this period of sleep is known as slow-wave sleep. Brain activity during sleep is significant for brain health and solidifying memories. Isn’t it fascinating to hear? Well, we know this because scientists can measure the brain’s electrical activity using electroencephalography (EEG) It also produces slow waves with relatively higher amplitude (Delta waves) and low frequency of around 1-4 Hz. 


Well, sounds complicated? We understand, let’s simplify it for you! You may have heard that we need at least 7 to 9 hours of sleep each night to function properly but what matters more is the quality of sleep you get. While your body rests, it goes through multiple stages of the sleep cycle and deep sleep is an integral part of that sleep cycle. It is the stage that you need to feel rejuvenated and fresh when you wake up in the morning. Deep sleep takes place when your body and brain waves slow down, which is why it’s so tough to wake up from deep sleep, and even if you do so, you will end up feeling super groggy and woozy!

Scientifically, the initial part of the wave is indicated by a downstate- which is an inhibition period where the neurons in the neocortex are silent. It’s during the period of deep sleep that the neocortical neurons can rest. The next part of the wave is indicated by an upstate- an excitation period where the neurons fire briefly at a rapid rate. *neuronal firing takes place as communication between neurons through electrical impulses and neurotransmitters. In contrast with (REM) Rapid Eye Movement sleep, the most significant characteristics of slow-wave sleep or deep sleep are slow eye movement, moderate muscle tone, and lack of genital activity.


How are Non-REM and Deep Sleep Connected?

There are two major sleep stages: Non-Rapid Eye Movement (non-REM) sleep and Rapid Eye Movement sleep (REM)

Deep sleep is the third stage of non-rapid eye movement (non-REM) sleep. More coherently, this is where your brain waves are at their slowest, and your heartbeat and breathing slow down. During deep sleep, your body goes through a myriad of essential processes for maintaining the optimal functioning of your brain. Ever felt like not getting up at all and sleeping in your comfy bed no matter what? Hah, we thought so! Research shows that for several minutes or even hours (sometimes) after you have been awakened from a deep sleep, your mental performance falls and gets impaired. So even if you wake up and get out of your bed, you’ll still have a very strong desire to go back to sleep. This concept is known as sleep inertia, the period of impaired performance and grogginess experienced after waking. 

Main features and Benefits of deep sleep

Deep sleep is critical for all of us.
Your memory of facts, information, and events from your day-to-day life, improves drastically. What’s more amazing is that growth hormones that help with organ, tissue, and muscle repair are also released from your pituitary gland. 

For example, if you’re recovering from an injury, deep sleep is the time when your body does the most work in healing itself.

Note: On the contrary, sleep disorders like nightmares, bedwetting, sleep eating, and sleepwalking are likely to occur during deep sleep.

    1. Electroencephalography (EEG) demonstrates high amplitude (Delta waves) and low frequency.
    2. High arousal threshold
    3. Consolidation of memories, information, and facts
    4. Recovers muscles, tissues, and organs
    5. Cell regeneration and increased growth
    6. Increasing blood supply to muscles
    7. Strengthening the immune system
    8. Lower chemicals that cause inflammation
    9. Help vaccines work better in your body 
    10. Keeps your heart happy

Stages of Sleep: Let’s understand the process!

The body cycles through three non-rapid eye movement (NREM) phases of sleep followed by one rapid eye movement (REM) sleep stage. It mostly takes between 90-120 minutes to cycle through all four stages of sleep after which your cycle restarts again. Usually, in the first half of the night, you spend more time in NREM sleep. However, as the night moves ahead, you spend more time rejuvenating and relaxing, i.e. in REM sleep.

Non-Rapid Eye Movement (NREM)
Sleep encompasses three sleep stages, referred to as stage 1, stage 2, and stage 3 NREM sleep.

Stage 1: The first stage of our sleep cycle is a transition phase during which the body and brain shifts from a state of wakefulness to going slowly into sleep. This stage is relatively shorter than the others, lasting for a couple of minutely and the sleep is lighter and can easily be disturbed. During stage one, the brain and body unwind and disentangle from the wakefulness. 
The brain waves also start to slow down as brain activity and responses to sensory stimulation decrease. This brief drowsy stage marks the beginning of going into sleep while the body starts to slow its rhythms down during this stage. 
Stage 2: The second stage of non-REM sleep is also a lighter stage of sleep that takes place when the body starts transitioning to deeper sleep. We spend most of our time sleeping, in this stage- about half of our total sleep every night is spent in the second stage itself. The heart rate and breathing rate slows down even more.
The muscles rejuvenate and relax furthermore and eye movements slowly stop. Your temperature drops and muscles start to relax as small bursts of electrical signals take place in the brain.
Stage 3: The third stage is the stage of deep sleep or slow wave sleep. This stage takes place for longer periods during the first part of the night. In this stage, our heart rate and breathing rate are at their lowest and most consistent during this part of the sleep cycle.
It’s difficult to wake someone from this stage. Most sleep disorders such as sleep eating, sleep walking, and night terrors happen while someone is in deep sleep. This is when brain waves are at their lowest frequency and highest in amplitude.

Rapid Eye Movement (REM) 

Rapid Eye Movement

As the name suggests already, your eyes move quickly beneath your eyelids during REM sleep. Do you know what’s even more fascinating? Your brain activity is very similar to that of a person who is awake but you lack muscle tone and hence don’t move. Research shows that most of our dreaming happens during the fourth stage i.e. REM sleep. The brain temporarily paralyzes the muscles to prevent the body from acting out the dreams.

The body first goes into REM sleep about 90 minutes after falling asleep, during which the eyes move back and forth behind the closed eyelids. The heart rate and breathing rate speed up and the rhythms sometimes become irregular. However, it’s super easy to wake up from this stage of sleep because you’re closest to the awake state. In REM sleep, the brain waves mostly send those waves to that of the wakeful state. 

Signs You’re Not Getting Enough Deep Sleep

Not getting a good night’s sleep can contribute to feeling cranky and fatigued all day long. Sleeping and eating are entangled from birth, they’re inevitable and necessary for survival. If you don’t get enough sleep, it will disrupt your circadian rhythm (an internal process that regulates sleep)

Being deep sleep deprived can make you feel a lot of things like: 

  • Less satisfied with food 
  • Less focused 
  • Short-tempered 
  • Irritated and annoyed
  • Trouble learning and consolidating memories
  • Less energetic 
  • Falling sick more often
  • Feeling drowsy and lethargic 
  • Reduced alertness and attention 
  • Cravings for high-calorie food
  • Constant mood swings 

Poor quality sleep can take a toll on your mental and physical well-being. It’s very closely linked to health conditions like mood disorders, migraines, heart disease, high blood pressure, Type 2 diabetes, Dementia (and Alzheimer's), and obesity. It’s not only calming and soothing to get a good night’s sleep, but it’s also inevitably important to have a stable psychological and physiological system to fight off every adversity that life throws at you! 

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Tips to Improve Deep Sleep: We’ve Got Your Back!

Tips to Improve Deep Sleep: We’ve Got Your Back!

Ensuring you get sufficient sleep overall, despite the stages, can help you get the “deep sleep” you and your body need to function properly. From developing a healthy sleep routine for your body to establishing a consistent sleep schedule, every small step you take towards your health and well-being can help you get a deep sleep you need to get all the benefits of deep sleep there are. Practicing good sleep hygiene can save you a lot of trouble, trust us, sleep isn’t something you want to trade for anything!

The most important thing that you can do to increase your amount of deep sleep is to allow yourself an adequate amount of sleep time. Falling asleep for some can be tough and we understand that so here are some steps you should practice to encourage more deep sleep: 

  1. Say bye to distress with exercise: Exercising is very helpful in reducing anxiety and improving sleep habits. Try not to do that right before sleeping though, it might end up keeping you awake. Instead, take several slow and deep breaths whilst paying attention to the air entering and leaving your body.
  2. Routine is the key: Try waking up and going to sleep at the same time daily. Create a routine that works best for you and stick to it!
  3. Caffeine before bed is a NO-NO: Stick to water or other decaffeinated drinks before bed. Stimulants like caffeine, alcohol and nicotine can mess up your sleep cycle really bad. The best is to stay hydrated, lovelies
  4. Create the perfect environment: Make your room; a comfortable space for you to sleep in. Altering light, sound, and temperature can help you get a good night’s rest/ sleep. The cooler and darker your space is, the better for you. *Try out our TENCEL™ bedsheets to experience the magic! 
  5. Get up if you feel uncomfortable: Ah, do anything but lay in bed tossing and turning, trying to get some sleep. Consider getting up and doing some light activity you enjoy until you’re tired of it! 
  6. We love a warm bath: Heating your body at least an hour before bedtime will help you induce slow-wave sleep/ deep sleep. The process of dissipating warmth from hands and feet can help you cool down later to a comfortable temperature for sleeping.
  7. Eat Healthy: What you have before bedtime impacts your sleep more than you know. Maybe try almonds, kiwi, walnuts, or chamomile tea before you hit the bed. They’re known to induce deep sleep better!
  8. Try these sounds out: Sounds like Classic White Noise and Pink Noise can help you get the appropriate amount of deep sleep. (Researchers found that steady pink noise and classic white noise reduce brain waves, which increases stable sleep)

Heavenluxe Tip: Get into your most favourite and comfortable loungewear and get all cool and relaxed in your TENCEL™ bed sheets that are super absorbent and breathable. *Sleeping in a colder room will help you drop to that level faster, which will assist you to fall asleep (and stay that way) quicker. We hope you try the above tips and tricks and get the deep sleep you totally deserve.


What is deep sleep or slow-wave sleep?

Deep sleep or slow-wave sleep is a phase of sleep where brain waves slow down, and the body undergoes physical restoration and repair. It is characterized by high-amplitude, low-frequency brain waves.

How long does deep sleep last?

Deep sleep lasts for approximately 20-25% of a person's total sleep time. This means that for a typical 8-hour sleep, deep sleep will last for 1.5-2 hours.

What are the benefits of deep sleep?

Deep sleep is essential for physical restoration and repair, as well as memory consolidation and cognitive restoration. It also plays a crucial role in immune system function, hormone regulation, and emotional regulation.

What factors can disrupt deep sleep?

Factors that can disrupt deep sleep include noise, light, temperature, stress, alcohol, and certain medications. Additionally, sleep disorders such as sleep apnea can also disrupt deep sleep.

What are the consequences of not getting enough deep sleep?

Not getting enough deep sleep can lead to physical and cognitive impairments, such as fatigue, weakened immune function, impaired memory consolidation, and mood disturbances. It can also increase the risk of chronic health conditions such as obesity, diabetes, and cardiovascular disease.

How does deep sleep differ from REM sleep?

Deep sleep and REM sleep are two distinct phases of sleep that alternate throughout the night. While deep sleep is characterized by slow brain waves and physical restoration, REM sleep is characterized by rapid eye movements and dreaming.

What can I do if I am having trouble getting deep sleep?

If you are having trouble getting deep sleep, it is recommended to consult with a healthcare professional to rule out any underlying medical conditions. Additionally, practising good sleep hygiene, such as establishing a regular sleep schedule, creating a relaxing sleep environment, and avoiding stimulating activities before bedtime, can also improve the quality of your sleep.