Rapid Eye Movement (REM) sleep first occurs around 90 minutes after we fall asleep and recurs in cycles throughout the night. During this cognitively restorative sleep stage, our brain activity picks up, nearing levels seen when we are awake, and we experience lucid, vivid, and emotional dreams.
REM sleep allows our minds to cleanse negative experiences and absorb fresh information. It provides time and space to analyze information and decipher patterns and problems. It acts as an emotional counterbalance, helping us stay calm and regulated in our lives.
The coolheaded ability to regulate our emotions each day - a key to what we call emotional IQ - depends on getting sufficient REM sleep night after night.
Dr. Matthew Walker,
Why We Sleep
Although we are unconscious during REM sleep, our bodies are hard at work - repairing, nourishing, and restoring. Our eyes flick from side to side, our hearts pump faster, and our diaphragms contract.
In REM sleep, our brain activity spikes, almost mirroring that of wakefulness, and we can experience the most vivid types of dreams. Amid the maelstrom, our brain stems send signals to relax our muscles so we don’t act out dreams.
Once, the REM sleep stage was called active sleep - and for good reason.
During REM sleep we receive a form of emotional first aid and a boost to creativity. It stitches information together so that we wake up with solutions to previously difficult problems that we were facing.
Learn more about sleep stages in Matthew Walker’s TED talk,
A walk through the stages of sleep
When we enter REM sleep, our bodies open up their limbic systems. Activity sparks in the hippocampal region and amygdala as the brain undergoes a sort of emotional cleansing, clearing out negative or disruptive thoughts.
Meanwhile, our brains organize their declarative memory - the factoids, Post-it notes, and Polaroids acquired over the course of a day.
As we progress to the latter half of the night, our brains switch from declarative to relational memory processing. They take these factoids and draw relationships between them. With fresh mental connections, problems that felt opaque and impossible the day before appear obvious the morning after.
While precious and valuable, REM sleep is difficult to safeguard. Since this sleep stage is more prevalent in the latter half of the night, staying up too late or getting up too early can cost us disproportionate amounts of REM sleep.
Consider someone who normally goes to sleep at 10 p.m. and wakes up at 6 a.m. If they choose to wake up earlier one morning - at, let’s say, 4 a.m. - they might lose only 25% of their total sleep time, but could easily lose half of their REM sleep.
When sleep is abundant, minds flourish. When it is deficient, they don't.
Dr. Matthew Walker,
Why We Sleep
The brain will do anything it can to claw back lost REM sleep, particularly if someone is struggling with the very things it supports - mental acuity, emotional regulation, memory formation. Those with sleep deprivation or a glut of anxiety or depression often move more rapidly into REM sleep. But this automatic compensation is a blunt tool.
The brain is amazingly plastic. It loves to repair itself and will do its best to stabilize things. But it cannot compensate back to normal. Someone with sleep deprivation will struggle to live their best life.
Param Dedhia, MD
Actual quality of sleep goes much further than just getting eight hours of rest. Sleep is contextual, personal, and dynamic. It is impacted by our environment, personal health, and life choices, and continues to change and evolve over time.
Improvements in the quality of both REM sleep and sleep as a whole rest on three fundamental pillars:
Sleep has a natural cadence and flow. By sleeping for long enough, you create enough opportunity for REM sleep.
Fragmented sleep is not restorative sleep. By achieving efficient, unbroken sleep, you ensure you reach later stages like REM.
All stages of sleep are important and all have a purpose. Creating the opportunity to cycle through most or all of all five vital sleep stages, including REM, allows you to achieve restorative sleep.
But the quality of our sleep is significantly influenced long before our heads hit the pillow. What we do during the day and how we prepare for sleep influences sleep experience and outcomes.