Living without REM sleep or ‘rapid eye movement’ sleep is like leaving your computer permanently switched on. After a while, it slows down, eventually crashing.
REM Sleep and Non-REM sleep are two strikingly different components of our slumber. Studies of brain activity throughout the night show us that our brain behaves very differently in REM and non-REM sleep. The difference is as marked as the difference between full wakefulness and loss of consciousness! In fact, brain activity during REM sleep is at least as active as during full wakefulness. Unlike non-REM sleep when brain activity slows as we fall into deeper states of sleep.
Brain Waves During Sleep
It’s interesting to note that while brain activity picks up during REM sleep, we experience a loss of muscle tone. Our physical movement is restricted so that we can’t act out our dreams, our limbs become completely limp while our eyes rapidly flit from side to side and up and down, hence the term ‘rapid eye movement’. Deep in our brains, there appears to be increased activity in the hippocampus and amygdala, the regions responsible for organizing long-term memories and regulating our emotions.
REM is the golden time of our sleep, a stage we should pass through 5 times each night, during which our brains prioritise and delete the data gathered throughout the day. Establishing memories and balancing our emotions. The remaining 80% of the night is spent in non-REM sleep, during which breathing slows, blood pressure decreases and body temperature lowers, allowing cells to grow and physical recovery and restoration to take place.
A short or disturbed night can compromise our REM sleep, resulting in a jet lag like daze, forgetfulness and irrational feelings.
People often ask how much sleep is enough? Typically getting an answer of 7 to 8 hours. Whilst this is true, in part, good sleep is not really about sufficient time in bed but about sufficient REM. During the night we cycle through varying depths of sleep, a bit like a repeating journey down into a valley and up a to a mountain’s summit. The mountaintop is the period of REM sleep with the valley bottom representing deep Stage 4 sleep.
Early in the night, our sleep restores our body, rebuilding muscles and digesting food. After around 60 minutes we drift towards lighter sleep before entering the first period of REM sleep for just a few minutes. This full cycle typically lasts for around 90 minutes before repeating. Each journey into REM is longer than the last and all research into what our brains are doing during REM suggests this really is a critical time for our learning and emotional wellbeing.
A good night’s sleep takes us deep into the valley (Stage 4 non-REM) and up to the summit (REM) as many as 5 times!
So, how can we ensure we are getting enough REM sleep? Firstly, if you are someone who wakes during the night, this doesn’t necessarily mean you aren’t getting enough REM. Before and after REM, our brains enter an almost wakeful state. If you wake from a dream the chances are you have just completed a period of REM. Once you get back to sleep you can re-enter the next 90-minute cycle, so long as you pass through four or five cycles per night and don’t feel unduly tired the following day, waking during the night needn’t be a cause for concern.
What should be guarded against are substances and practices that inhibit REM:
- Alcohol has the sedative effect of inducing drowsiness and non-REM sleep but nightcaps have been found to inhibit REM sleep.
- Alarm clocks are often set to interrupt us during the final, longest phase of REM at the end of our final sleep cycle. Try to establish a bedtime that enables you to wake naturally before the time you need to get out of bed. Thereby ensuring that most precious, final 15 minutes of sleep isn’t interrupted.
- Some medicines can impact our sleep patterns, ironically this includes drugs prescribed to help people sleep such as antidepressants and hypnotics. Like alcohol, they can help us to relax and get off to sleep but if they later disrupt our sleep cycles and REM sleep, their sustained use will trigger additional mental ailments.
As the chart at the top of this page shows, we get our fifth and longest dose of REM towards the end of the night. If you find your alarm is regularly waking you and interrupting a memorable dream, your wake time is compromising your REM sleep. By simply bringing forward your bedtime enough to wake naturally, or at least not mid-dream you can ensure a full dose of REM and maximum memory retention and emotional restoration.