Newborn sleep cycles
REM and Non-REM Sleep
Ever wonder why newborn sleep is such a novelty?
There is a reason why newborns have vastly different sleep patterns than adults do. They are biologically wired differently when it comes to sleep and are incapable of sleeping the way we do because of their unique sleep cycles.
Let’s break it down:Newborns cycle through two stages of sleep, REM and non-REM sleep . (Active and quiet or deep sleep). The non-REM sleep is not yet differentiated into 3 stages, but that begins to evolve over time at around 3-5 months of age. By about 3 months old, babies enter non-REM sleep first and by about 6 months old the non-REM sleep is differentiated into 3 distinct stages.
REM sleep is the lightest stage of sleep where dreams occur and although newborns wake more often when in this stage, a lot of growth and goodness takes place here as well.
How long is an infant's sleep cycle?An Infant’s sleep cycle is usually 40-50 minutes long whereas an adult’s is about 90 minutes. This means that they are completing a sleep cycle much quicker and spending a lot of time in REM (active) sleep which can explain why they wake more frequently and are often in a light sleep. Adults spend about 20% of their sleep in REM, newborns spend about 50% in REM and premature babies spend about 80% of their time in REM sleep.
Did you know that it’s normal for infants to wake or have partial wakings after they complete a sleep cycle? And if they are unable to fall asleep independently, they will not be able to connect one sleep cycle to the next and the inevitable happens, they wake up…and cry. They’re usually saying “help, I am not quite ready to wake up yet, so please put me back to sleep”. Thankfully, though, as their sleep patterns mature with age, the length of their sleep naturally lengthens as well, albeit often with our encouragement and guidance.
I never knew infant sleep could be so interesting, nor did I ever imagine sitting in the early morning hours writings about it (yes, I am a total early-bird)!
Are they asleep or awake?We can be easily deceived by our newborns while they are In REM sleep, as they often seem like they’re awake, making faces, grunting, squirming, rolling their eyes, laughing and smiling, etc…don’t be alarmed as this is all normal behavior for a newborn during this stage of sleep. Unlike adults who have motor inhibition during REM sleep, newborns do not yet have this motor inhibition, which helps explain all of that movement. At around 3-4 months of age, their motor activity during REM sleep decreases, becoming more inhibited (REM sleep muscle paralysis or muscle atonia are other ways that define this motor inhibition). This is a normal function of REM sleep and it will develop more as the baby gets a bit older and as his sleep cycles mature.
In nREM/quiet sleep they are in a much deeper sleep and are more difficult to wake. This is where they usually do their longer stretches of sleep and where they lay more still.
How much sleep do babies get in a 24 hour period?Newborns sleep for about 14-17 hours in a 24 hour period, approximately 9 of those hours are spent in REM sleep (about 50% of their total sleep).
Babies 6 months and older sleep about 12-15 hours in a 24 hour period where their REM sleep decreases over time and their non-REM splits into distinct stages, mimicking sleep patterns similar to adults.
The Importance of REM and Non-REM sleep
We briefly went over the different stages of sleep that newborns cycle through, but now I’m going to tell you the importance of both REM (Rapid-eye-movement) and Non-REM sleep, which applies to everyone, not just newborns.
In REM sleep (active sleep)…Neural connections are made during REM sleep which promotes brain development.
REM helps the brain retain long and short-term memories, helps us process our emotions as well as all other information and stimuli that we experience throughout the day. Studies have shown that people have trouble retaining short and long term information without REM sleep.
REM sleep optimizes mood and coping skills, brain development and cognition.
In REM sleep energy is provided to the brain and body. Blood flow breathing and brain activity increase. Heart rate speeds up, breathing is irregular and the body experiences temporary loss of muscle tone, often referred to as muscle atonia - which is a normal function of REM sleep.
In non-REM sleep (quiet/deep sleep)...This is a very deep and restorative stage of sleep. The body does most of its repairs and regeneration in Non-REM sleep.
Stage 1: Heart rate begins to drop, muscles relax, and breathing slows. Some people may experience some body and eye twitches, called hypnic jerks, but overall motor activity begins to decrease.
Stage 2: The heart rate continues to slow down, body temperature begins to drop and we spend about 50% of our total night time sleeping in stage 2.
Stage 3: Tissue growth and repair occur, blood supply to the muscles increases, essential growth hormones are released for bones and muscle growth. Stage 3 also helps regulate our glucose metabolism and strengthens our immune system.
These are just some of the many amazing things that take place during REM and non-REM sleep and I hope this has given you a better understanding of our sleep cycles and their unique differences.
