REM versus Non-REM Sleep Stage

On way to comparing sleep stages of REM and Non-REM

I have been interested in learning about what happens during sleep for a while. Since the amount and quality of sleep we get can affect our health drastically, learning the difference between the REM and Non-REM sleep stages might be helpful. The sleep occurs in five stages and the dreams occur during the REM stage. Here are some of the interesting features and distinctions between the rem sleep and non-rem sleep:

Our sleep goes 4 Non-REM stages followed by a REM stage. During a normal sleep, one sleep cycle could average around 90 minutes; however, REM period gets longer and longer in each succeeding cycles. Now what I find interesting is that if we are sleep deprived, our REM period comes not only sooner, but is also longer compared to a non-deprived sleep due to REM pressure. So REM is longer when sleep deprived. This is little contrary to what our regular sleep cycle features – that with each sleep cycle, as our sleep deprivation lessens, REM period gets longer.

Also in our textbook, The Promise of Sleep, on page 21, Dr William Dement provides an example of young boy (the age that usually shows the perfect sleeping stages as exemplified by their near-perfect brain waves) to explain sleep stages. After stage 4, he talks about the reemergence stage 3 briefly before going into REM stage. Before reading that passage, I was under the impression that we always go through stage 1 through 4 sequentially before falling into REM stage.

Non-REM sleep involves theta waves during first two stages and delta waves of deep sleep during the last two stages. However, REM sleep is far more similar to alpha and beta waves of wakefulness involving lower amplitude and higher frequency than theta and delta waves of Non-REM sleep. Other than this brain wave activity, all other differences such as inhibition of muscle activity, and increased rates in heart beat, blood pressure, respiration and blood flow to the brain during REM all makes sense since we are dreaming and involves physiological activity (such as sympathetic nervous system) although not overtly as in our body’s muscle or motor movements.

Sources:

Information about Sleep. (n.d.). Sleep, Sleep Disorder, and Biological Rhythms. Retrieved

August 31, 2012, from http://science.education.nih.gov/supplements/nih3/sleep/guide/info-sleep.htm

Dement, W. C., & Vaughan, C. C. (2000). The promise of sleep: The scientific connection 

between health, happiness, and a good night’s sleep. London: Macmillan.