We cycle between REM and non-REM sleep. First comes non-REM sleep, followed by a shorter period of REM sleep (approximately 90 minutes after you have fallen asleep and lasts around ten minutes), and then the cycle starts over again. Each of your later REM stages gets longer, and the final one may last up to an hour. Your heart rate and breathing quickens during each REM.
REM stands for rapid eye movement. During REM sleep, your eyes move around rapidly in various directions but don’t send any visual information to your brain. That doesn’t happen during non-REM sleep. Dreams typically occur during REM sleep & some studies show REM is when many of our brain’s waste products and other unhelpful proteins are removed, eventually helping our memory & cognitive functioning in the daytime.
Everyone dreams anywhere from 3 to 6 times each night. Dreaming is normal and a healthy part of sleeping.