Why should I sleep at night?

Q:  I am having trouble sleeping.  Because I work a swing shift, I am thinking of breaking up my sleep periods into two 4-hour blocks, one very early in the morning, and one in the early afternoon.  In terms of improving sleep, is this a good idea?

A:  As we all are unique individuals with unique needs, the answer will be unique to you. 

That said, in general we as human beings have evolved over the eons to sleep  in one sustained period of rest.  Unlike cats and dogs, which are polyphasic sleepers (usually catching several naps throughout a 24 hour period), we are more or less  monophasic.  That’s the way our sleep systems have evolved and seem to work best.

Two of the most important controllers of sleep — circadian rhythm and sleep drive — are keyed to one unbroken period for sleep at night when it’s dark, and one more or less unbroken period for wakefulness and activity, during the day when it’s light.  A number of our physiologic and neurologic systems also support this pattern.

One common exception to the unbroken monophasic pattern is the early to mid-afternoon nap, when we normally experience a dip in the circadian rhythm.  This dip in fact is built into a number of cultures as a siesta.  Many of us find it easy and very refreshing to take advantage of a short cat nap in the early afternoon, without much disruption to our homeostatic sleep drive.

The short afternoon siesta should not be confused with the kind of 4-hour period for sleep you are describing, when your mind and body would presumably go through several deeper NREM-REM cycles.  That would understandably reduce sleep drive significantly that night, making it much harder to sleep well.

However, some people can temporarily become more polyphasic in certain situations.  Long distance competitive sailors come to mind.  These are people who compete in long trans-oceanic races.  They may catch several short power naps throughout a 24-hour period, enabling them to trim sails, make course corrections, monitor currents and so forth, which gives them a competitive advantage as they cross long distances over many days.

Astronauts, firefighters, and combat soldiers are more examples of people who can temporarily become more polyphasic and yet still perform at a very high level.  That’s hope for the rest of us living our normal everyday lives who may not get a perfect 8 hours of sleep.  This is evidence we can still function at a reasonably high level the next day.

Your bi-phasic sleep schedule may work for you, at least temporarily.  The only way to tell for sure is to try it out and see what happens.  But we suspect if you are already having trouble with sleep this won’t help.

Instead of two sleep periods, you might do better with scheduling one unbroken period for sleep.  This might help you even if you sleep during some daylight hours and work during some nightime hours.  Shift work is very challenging for sleep, but in general a better strategy might be going for the most consistency possible in your sleep-wake schedule.

By consistently getting up at the same time, you re-set and re-synchronize your circadian rhythm, sleep drive, and biological clock every day.  All of these are key regulators involved with producing good sleep.

Explore posts in the same categories: Health, Insomnia, sleep

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One Comment on “Why should I sleep at night?”

  1. fxbass Says:

    I’d recommend reading the blog of a guy named Steve Pavlina. He did some biphasic and polyphasic sleep experiments a couple of years ago, and posted a series of posts on how it all went.


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