While the premise of your eyes darting around while you’re asleep might sound slightly creepy, rest assured that it’s anything but. Known as rapid eye movement (REM) sleep, it’s simply one of five cycles your brain goes through while you’re sleeping. REM sleep makes up about a quarter of your sleep cycle and first occurs 70 to 90 minutes right after you hit the snooze button.
During REM sleep, both your body and brain are actually in high activity and as such, dreaming happens. It begins in direct response to signals sent to and from different parts of your brain. Signals are first sent to your brain’s cerebral cortex, the part responsible for learning, thinking and compartmentalising information.
These signals are also sent to your spinal cord in order to shut off movement, hence creating a temporary inability to move muscles in your arms and legs. In some instances, abnormal disruption of this temporary ‘paralysis’ may cause people to move while they’re in a dream state.
REM sleep is vital because it makes up the restorative part of our sleep cycle. If this is disrupted, your body won’t be able to follow its normal circadian sleep cycle and will instead slip directly into REM sleep as a result of not getting enough rest the night before.
Your body will be forced to go through extended periods of REM sleep until you catch up on this important stage of sleep. That’s why sometimes you can wake up feeling more tired and less concentrated than before!