A Perfect Night’s Sleep

15 Mar, 2010 || by

How did you sleep last night? When you put your head on your pillow, did you go straight to sleep or were you suddenly wide awake?  It has been estimated that as many as 40 percent of Americans will suffer from some form of sleep disturbance at one time or another.  If you have trouble sleeping — or waking up — this is the article for you.  Before we begin, answer these questions and solve an easy math problem:

* Do you wake up alert or groggy?
* How many hours do you sleep on an average night?
* Do you use a snooze alarm?
* Take the total number of hours you sleep and divide it by 1.5.

First, let’s discuss how sleep works.  We sleep in 90-minute cycles.  Think of each cycle as a “V.”  Imagine that the top of the “V” on the left side is the point where you place your head on the pillow upon getting in bed.  You take a little while to think over the day and say your prayers; then Mr. or Ms. Sandman shows up and off to sleep you go.  It takes 45 minutes to float down into the deepest point of your first sleep cycle.  If you’re awakened while in this stage of sleep, you’ll feel very disturbed.  But as soon as you reach this deep phase, you start on your way back up the right side of the “V” toward a lighter sleep.

It then takes another 45 minutes to waft upward to the top part of the “V” on the right-hand side.  The top of the cycle is the shallowest period of sleep.  During this time you dream and you can be easily awakened.  When you finish this 90-minute “V” cycle, you then enter a new cycle — down the left-hand side again toward the shallow sleep stage where dreams occur.  The cycles, then, look something like this “VVVVV” — up and down, up and down throughout the night, recurring regularly, approximately every 90 minutes, until you wake up.

So, you wonder, how can you use this information to your advantage?  That’s where your answers to the earlier questions come into play.  Let’s take a look at your answers in reverse order:

* Take the total number of hours you sleep and divide it by 1.5 (one and one-half hours of sleep). If you sleep an average of six hours per night, your sleep is divided into approximately four 90-minute sleep cycles.  If you sleep seven and a half hours per night, then you experience five 90-minute sleep cycles per night.  The trick is not to wake up while you’re somewhere in the deeper levels of the sleep cycle. Rather, you really want to awaken at the end of a sleep cycle, when the body is naturally primed to wake up.  Here’s a concrete example: Let’s say you go to bed at 11:00 pm, and your alarm clock is set to go off at 5:30 am.  That’s six and a half hours of sleep, or four cycles and some fraction left over.  When your alarm goes off, your body is descending into the deep-sleep phase of a cycle.  This isn’t good.  You will likely wake up feeling groggy rather than bright-eyed and bushy-tailed.

* How many hours do you sleep each night? Any answer is, of course, acceptable, but the ideal answer is in multiples of 90 minutes.  That means an individual should plan for six hours (four 90-minute cycles), seven and a half hours (five 90-minute cycles), or nine hours (six 90-minute cycles) of sleep each night.  Health experts have found the seven and a half hours is the amount of sleep most often associated with good health.

* Do you awaken alert or groggy? Once again, if you plan your sleep night in complete 90-minute cycles, you’ll wake up ready to go.  If you set your clock to wake up somewhere within a cycle, it will be harder to get up and get going.  Remember that your children sleep in cycles, too.  They’ll awaken more easily if you rouse them at the end of a sleep cycle (provided you know when it is that they actually go to bed).

* Do you use a snooze alarm? If you answered, “Yes,” then your alarm clock is probably set to go off when you’re somewhere in the middle of a 90-minute cycle rather than at the end of one.  So, you snooze, snooze, snooze…until you reach a point in your cycle where your body is ready to wake up.  Planning your sleep night in multiples of the 90-minute cycles and then setting your alarm accordingly will make your snooze alarm obsolete.

Bottom Line: If you plan your night of sleep in multiples of 90-minute cycles, your sleep will be more refreshing, and perhaps your dreams will be more pleasant.  It’s also more likely that you’ll wake up on the right side of the bed, which will be appreciated by all!


Buffington, Perry W. The Perfect Night’s Sleep. MJF Books, 1996

Dement, William C. The Promise of Sleep: A Pioneer in Sleep Medicine Explores the Vital Connection Between Health, Happiness, and a Good Night’s Sleep. Dell, 2000

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2 Responses to “A Perfect Night’s Sleep”

  1. I’ve read some good stuff here. Definitely worth bookmarking for revisiting.

  2. Hi,
    I have a little question. Does the sleep cycle start immediately after I put my head to the pillow ? if it isn’t like that, then should I place my alarm to start after 15 minutes or 25 minutes of putting my head to the pillow ?

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