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The Difference Between Deep Sleep and REM (and Why it Matters!)


Woman REM Sleep

When you hear those in the industry, like our Sleep Experts, speak, you may hear them say things like “Are you getting good sleep?” and “You need quality sleep.” Isn’t all sleep good sleep? Actually, no. You see, sleeping one hour at a time, eight hours in a day is not the same thing as sleeping for eight solid hours. Just ask the parent of a newborn and they will tell you that! All sleep is not the same, and because of this, all sleep is not restful or restorative. The question is: why?

There are actually different stages of sleep; each are important and each are unique. There are three stages of non-REM sleep, Stage 1, Stage 2, and Stage 3, and then there is REM sleep. Stage 3 is also known as “Deep Sleep.” Let’s look at each stage a little more:

Sleep Stage 1

 This the lightest stage of sleep. Muscle tone throughout the body relaxes and brain wave activity begins to slow, and you may even be able to still hear what is going on around you. Occasionally in Stage 1, you may experience hypnic jerks or abrupt muscle spasms or even experience the sensation that you are falling.

Sleep Stage 2

 In this stage, you are fully asleep and no longer able to easily be awaken. Your body temperature begins to decrease, and your heart rate begins to slow. You are now very much asleep.

Sleep Stage 3/Deep Sleep

Your body enters this Deep Sleep stage anywhere from a half hour to 45 minutes after falling asleep. Your breathing slows and your heartbeat is regular during this stage. The muscles in your body become completely relaxed, and you typically sleep through any external sleep distractions, like loud noises. If you do wake up during Deep Sleep, you will likely feel groggy and disoriented. Also, there are almost always no dreams during this period of sleep. Deep Sleep is extremely important to a person’s overall health, because it’s during this sleep stage in which the body naturally heals itself. During Stage 3, your body replaces cells, heals wounds, and builds muscle tissue. Your immune system also gets a boost in this stage.


Rapid eye movement, or REM sleep, is the deepest sleep stage and occurs about 90 minutes after you fall asleep. In this stage, your heart beats faster and will become irregular. As well, REM sleep is associated with intense brain activity. This is the stage where you’ll likely experience active and vivid dreams. REM sleep restores your brain and is important for your learning as well as your memory.

This cycle doesn’t occur just once; it repeats itself as you sleep throughout the night. If you get a full night of sleep, you will go through each stage up to five times.

As you can see, each stage is very distinct. Stage 3, or Deep Sleep, and REM both have valuable benefits to your body. In Deep Sleep, your body is healing itself, repairing from the day and making sure you are fresh for the morning. In REM, your mind is at work, restoring itself so your memory and brain function remain in peak condition. Sleep problems can cause issues with memory, thinking, mood, and chronic fatigue. Along with good nutrition, restorative sleep is vital for your optimal physical, emotional, and mental health.

When looking at this, it is very clear to see why getting the fully-recommended eight hours of sleep at night is so important to your overall health. If you are having trouble falling asleep, you won’t have enough time to get through each stage the appropriate number of times. Just as bad for your health, if you wake up frequently, you aren’t allowing your body to enter either Deep Sleep or REM. While Stage 1 and Stage 2 are important, this is not where any healing or restoration takes place, and your body will begin to feel the effects of not repairing itself very soon.

The good news is that now that you know this information, you can do something about it! If you suspect you aren’t getting the kind of sleep you need, each and every night, make today the day you do something about it. It could be that you need a few new pillows to better support your head and neck. Perhaps you need a new mattress, because your current one doesn’t fit your sleep needs. Maybe an adjustable bed to combat Restless Leg Syndrome would do the trick. A Sleep Expert at City Mattress can help you find exactly what you need in order to sleep better!