slow wave sleep

What Is Slow Wave Sleep And How Does It Affect Your Brain Health?

Published on February 27, 2023 – Last Updated on February 27, 2023

Because of the rigors and challenges of daily life, many people tend to forget how sleep could be vital to one’s overall health and well-being. There are even instances that one would prioritize other things like partying, spending time on digital devices, and binge-watching movies over eight hours of sleep. 

Not many people are aware that sleeping is a complex process with numerous stages. You don’t just shut your eyes and drift off. In fact, the two stages of sleep include REM or rapid eye movement, and non-REM, which is further divided into three stages from N1 to N3. Slow Wave Sleep (SWS), the last stage of non-REM sleep, is the most restorative stage of sleeping. 

After reading this post, you will better understand what SWS is, how it affects your brain health, and how to improve its quality. Additionally, you can click here if you want more information regarding the matter. 

What Is Slow Wave Sleep SWS?

SWS is a stage of sleep that occurs during non-REM sleep. As mentioned earlier, it’s the last stage, which is also called N-3 or delta sleep. 

In non-REM sleep, N1 is the period between wakefulness and sleep, and it lasts for only five to ten minutes. This is the period when your brain prepares your body to sleep, and you can easily be woken up by even the lightest scratch. You will then experience N-2. It is when you slowly lose awareness of your surroundings and prepare for your deep sleep, which typically lasts for about 20 minutes.

N-3 is when your brain experiences slow brain waves called delta waves. Hence, it is called Slow Wave Sleep. During this period, your brain activity slacks, and your body temperature, blood pressure, and heart rate take a downturn. This is the stage when you’d be so difficult to wake up because this is when your brain is restoring its strength and function. 

When you sleep, your body cycles through all stages at least four to six times a night, with each stage averaging 90 minutes.

Why Is Slow Wave Sleep Important?

SWS is critical for many functions of the body, including physical and mental health. This is also when vital hormones like melatonin, leptin, and growth hormones are released to perform essential functions in your body. SWS is also found to be instrumental in memory consolidation. This is when the brain consolidates memories by transferring them from the hippocampus to the neocortex, where they are stored as long-term memories.

How Does SWS Affect Your Brain Health?

slow wave sleep brain health

Fun fact, your brain releases toxins and waste products. And it happens during Slow Wave Sleep. Your brain’s glymphatic system, which helps clear waste products, is most active during this stage, so it’s imperative to get at this stage of sleep to get rid of toxic thoughts that may trigger stress and burnout.

No wonder people would say, ‘you can sleep on it ‘ before you decide on anything important. Sleeping gives your brain a clean slate to process new information and think more objectively. You definitely can’t do that when you barely slept. 

More importantly, this process is crucial because it helps to prevent the accumulation of toxic proteins, such as beta-amyloid and tau, which are associated with the development of Alzheimer’s disease.

Aside from getting rid of toxins, SWS helps the brain by strengthening the connection of synapses. Synapses are essential because it allows your brain to learn new things by making the connections of neurons more efficient. At this stage of sleep, your brain does synaptic pruning. This is a process wherein the brain chooses connections to eliminate—those you don’t need—while strengthening those important to you. This process is just like deleting files from your computer to increase your storage and save new photos or videos.

How To Improve Slow Wave Sleep?

Now that you know the importance of SWS, here are several ways to improve its quality:

  • Stick to a regular sleep schedule – Going to bed and waking up at the same time every day can help regulate your circadian rhythm and improve the quality of your sleep.
  • Make your sleep environment relaxing – Make your bedroom has a cool dark, and quiet, and avoid using electronic devices before bed.
  • Avoid caffeine and alcohol – These substances can interfere with sleep and prevent you from getting enough SWS.
  • Exercise regularly – Regular exercise can improve the quality of your sleep, including SWS.
  • Practice relaxation techniques – Techniques such as deep breathing, meditation, and yoga can help reduce stress, promote relaxation, and help you sleep better.


Your body gives you many cues if you’re tired or sleepy, so don’t resist it. Treat your body well and nourish it with good food, great company, and restorative sleep. Doing so will give you more time to enjoy life with a healthy and sound body and mind. 

Now that you know the importance and benefits of SWS, don’t hesitate to invest in a cozy room and bed, say no to late-night partying, and give in to your body when you need to lie down and rest.

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