REM, like other stages of sleep, is a biological necessity.  When we don’t get enough REM, our brain will compensate by promoting REM whenever possible.  This is called REM Rebound.

It’s thought that this phenomenon is a way for our bodies to tell us to get more uninterrupted sleep.  It tends to affect those who constantly disrupt their sleep schedules, due to work, travel, or other needs.

We usually run into REM Rebound sleep when we’ve only had four hours sleep or less the night before.  If we then lie down to take a nap, our brain will shift immediately into REM sleep before fulfilling the need for Deep and Light sleep.

In extreme cases, such as those brought on by sleep deprivation torture, we will start hallucinating and experiencing REM-like dreams with our eyes open!

Unfortunately there is no way to “cheat” your brain into dealing with less REM.  The REM Rebound pattern will continue until one’s sleep debt is paid off – a process that can last as long as month.

It should be noted that some people do suffer from a condition known as Excessive REM Sleep, and that intrusion of REM into the early part of one’s sleep cycle could be a sign.  However Excessive REM Sleep is usually a symptom of a larger health condition, such as depression or narcolepsy.  If you sleep for more than 10 hours a night and much of it is REM sleep, this could be a strong signal to seek a professional opinion.

Lastly, REM sleep is a very active sleep stage for our brains – sometimes more active than Wake!  As such sleep scientists often misread Wake as REM and Zeo, which uses the same scoring criteria as professionals, can also make a similar mistake.  If you sleep 7-9 hours each night and don’t have signs of Excessive REM (usually half the night or more), then it’s also possible that some of these brief REM periods at the beginning of the night were Wake.