Sleep research is a fascinating topic. When you think about it, each of us spends close to one-third of our lives in an unconscious state (if we’re getting the recommended amount of sleep, that is). While many more facts about sleep are yet to be uncovered, here’s what we do know and why this information can help you get more out of your sleep time.
The 90 Minute Cycle
Current research shows that as a person sleeps through the night, the nature and quality of sleep follows a predictable cycle, which consists of five phases: 1) light sleep, 2 ) medium sleep, 3) deep sleep, 4) very deep sleep, and 5) rapid eye movement (REM) sleep, which is the phase in which dreaming occurs. Each complete cycle runs about ninety minutes and then starts over. This means that a person getting six hours of sleep completes four full cycles.
The Differences between Cycles
Newer research is discovering that the time spent in each phase of each cycle shifts through the night. For instance, people have more deep sleep in the earlier cycles and more REM sleep in the later cycles. Even more curious is the finding that people who go to bed early experience more deep sleep while people who go to bed late experience more REM sleep.
How to Wake Up Earlier Than Usual without Feeling Groggy
Each of us has probably endured being jolted out of a deep sleep by an alarm clock. You feel groggy, out of it; the term “brain fog” is good description. The next time you need to get up earlier than usual, use the knowledge of the cycles to prevent or minimize that grogginess. Figure out what time you need to get up, and then make sure you go to bed early enough so that you sleep in a number of complete cycles. For example, if you need to get up at 4:30 a.m., go to bed six or seven and a half hours earlier, which would be 10:30 p.m. or 9:00 p.m. That way, when 4:30 rolls around, you’ll be at the end of an REM phase in the cycle as opposed to the middle, deep sleep part of a cycle.
*Psychology Today (July 6, 2013)