Trapped in a Nightmarish Spiral: How Sleep Deprivation Results in Troubling Dreams

 

          You know that feeling when you are being chased down a dark alley and come across a dead end. Sweat drips down your sternum as your heart beats a million miles an hour, and then suddenly… you wake up. These hyper-realistic dreams are a result of a phenomenon known as REM rebound.

          Our most complex and vivid dreams occur in the final stage of sleep, known as REM (rapid-eye movement sleep). This REM period lengthens throughout the course of the night as you cycle through the various sleep stages, reaching its maximum duration just before you awaken. The REM portion frequently suffers the most when you get less sleep than the recommended 7 to 8 hours.  So when you do finally catch up on sleep, it comes to bite you back full force and brings with it more intense dreams.Psychologist Tore Nielsen, director of the Dream and Nightmare Lab at the Sacré-Coeur Hospital in Montreal conducted an experiment where he  monitored the brain activity of the participants as they slept and anytime it was observed that they were slipping into REM stage he would wake them up. Sometimes Nielsen would have to wake them 40 times in one night because they go directly into REM as soon as they are asleep due to the effect of REM rebound.  

          To understand the cause behind the result of Nielsen’s experiment, we first need to understand how our sleep cycle works. One sleep cycle lasts around 90 minutes and consists of 4 stages of non- REM and 1 stage of REM. The first stage of non-REM is the phase of dozing off between sleep and awakening. The brain slows down in stage two and only occasionally becomes active. When the brain enters stages three and four of slow-wave sleep, the heart and breathing rates drastically decrease and the brain essentially turns out. At this point we are in deep sleep. Our first REM cycle, which lasts just five minutes, begins after 70 minutes of non-REM sleep. After one cycle has finished, it repeats around 4-5 more times throughout the night. Non-REM phases get shorter as the night goes on and REM periods get longer, giving us a 40-minute dreamscape right before waking. However, this is only the case when the body is getting the recommended 7-8 hours of sleep. 

          Let’s say that you have been getting 5 hours of sleep during the week and decide to catch up on sleep during the weekend. During the days where you are sleeping less, your body will prioritize deep sleep meaning that it will cut down on the amount of REM activity and increase the duration of the non-REM cycles. When you sleep in on the weekend and get 7 plus hours of sleep, the REM density and duration will increase. The electrical activity in the brainstem that causes the eye movements will rise, which is associated with more intense dreams. Each REM phase lasts longer than the one before it, thus anyone sleeping for more than eight hours to catch up will have extra-long REM periods, which is not the case on other nights. On these nights you will experience hyper vivid dreams that are more intense than the ones you have had before.

So the best way to avoid REM rebound would be to stick to a healthy sleep schedule. Getting your daily 7-8 hours of sleep would mean that you don’t have to assign specific days to catch up on sleep and you would encounter less people chasing you with a knife in your dreams. However, scientists still haven’t figured out why the brain is so persistent in its need for REM. To understand its importance we would need to understand the importance of dreams and thought, something that is still being looked into.