Illustration: Ashley Siebels
Although sleeping can feel as effortless as turning off the lights and waking up feeling refreshed and rejuvenated, your brain is way more active at night than you may think.
While you sleep, your brain cycles through two distinct stages of sleep: rapid eye movement (REM) and non-rapid eye movement (NREM). The latter stage is broken down into three different pieces, and you can see how they differ in the infographic below, along with why REM stands alone as its own stage. You complete several full sleep cycles throughout the night, each lasting from 90 to 110 minutes, with your REM stages increasing in length as the night goes on. Keep reading to find out what’s really going on behind the scenes in your brain when you sleep.