Summer nap schedule

An experimental study from the 90’s and case study from Alaska

What time is bedtime in the summer? Can you fall asleep with the sun still on the horizon?

Summer, with its beautiful long days, is in full swing. I’ve written a lot about darkness and how it is necessary part of every day… but what about the endless summer days of the extreme latitudes, when the sun never sets? How can you have circadian health in such a climate?

Even where I live in Southern Oregon where the summer nights drop down to only ~8 hours of darkness, summer can feel tiring. It’s hard to fall asleep in the evening—still warm and bright—and then dawn seems to arrive so soon!

In summer sleep is vain; 
I barely close my eyelids when 
‘Tis time to wake again. 
~IRIU

The answer is to nap through the heat of the day. Naps can be short—just 20 minutes or less. Or, naps can be long and more of a second sleep (2-4 hours). And most likely, having an afternoon nap is the most physiologically and traditionally correct response to these extra long days.

This afternoon nap will reduce the amount of time you need to sleep overnight, which is perfect when the summer light and heat keeps you up past your normal bedtime.

It turns out, the idea of needing an 8 hour sleep at night might not be true under most natural lighting conditions.

When it’s accurate is in living under artificial lights on for 16 hours a day¹, and when these lights that are enriched with blue that stimulates cortisol and wakefulness as long as humanly possible. So in the modern era where this is the standard condition, it’s “normal” and “healthy” to work towards a consolidated 8 hour sleep pattern. But when light differs greatly from that (either much more darkness, or much less darkness), human sleep breaks into the more ancestral polyphasic sleep pattern.

So what I am describing with summer and fatigue is what people not doing “the circadian thing” most likely feel like all the time under their blue-enriched daytime light bulbs!

To recap: modern artificial light is compressing our sleep, and without it, human sleep would probably be polyphasic like everyone else in the animal kingdom:

Human beings do differ from other animals in that they use artificial light to create an unending 16-hour photoperiod for themselves. This fact raises the possibility that the sleep of human beings differs from that of animals because the artificial long photoperiod compresses and consolidates their sleep in an unnatural way. In other words, consolidated sleep in human beings may be an artifact of modern lighting technology. Indeed, in less structured conditions, human beings’ sleep can exhibit poly-, or at least bi-phasic patterns. This is true in infants, who sleep several times during the day and night, and in adults who nap. Furthermore, individuals who submit themselves to a regime of enforced bedrest in a monotonous environment for one or more days exhibit as many as four peaks per day in average 24-h profiles of their sleep.
~Wehr (1992)

There is not only experimental data as referenced above, but also human case studies showing polyphasic sleep patterns in both the darkness of winter as well as the brightness of summer.

Author Jean Craighead George.

Here’s an excerpt from author Jean Craighead George’s experience with experiencing long Arctic days as an outsider. Here’s the story in her own words:

Almost immediately, [the author’s son] Luke discovered that there was no running water in this hotel and that the ice in the drinker had been chipped off an iceberg. (The salt settles out of these oceanic glaciers and leaves them as fresh as a frozen spring.)

That night when we dined at an Eskimo restaurant, I ordered whale, and Luke ordered reindeer soup. Both were so rich and greasy that we could barely swallow them. Three days later, however, we were to discover that the body has its own intelligence. The cold had so changed our physiological needs, the whale, reindeer soup even blubber, tasted like filet mignon. We were burning fats as I burn wood in my fireplace in winter. Morning, noon, and night.

The element of the Arctic to which we never quite adjusted was the midnight sun. To Luke and me, the light seemed to say it was constantly four o’clock in the afternoon, no matter what the clocks said. After a few sleepless nights and after conquering the feeling that it was always time to quit work we observed that the Eskimos and birds handled this situation by disappearing around noon and midnight for two sleeps instead of one. 

Unfortunately, we never got an opportunity to join the birds and the Eskimos in their rhythmic naps during the endless day, for the gussaks had clocks and kept hours. Gussaks, by the way, is an Eskimo corruption of Cossacks, the first white men in Alaska. Eventually, we learned to solve our sleeping problem by pretending we were taking an afternoon nap. Exhaustion took care of the next 8 hours.

Newberry Medal Acceptance Speech, by JEAN CRAIGHEAD GEORGE (1973)

The interesting thing to me was she brings up 3 specific health practices:

1. Drinking glacier water

2. Burning fats through a ketogenic diet

3. Adopting a biphasic sleep schedule (half of sleep at midnight, the other half at noon)

But most sleep experts advise against a polyphasic sleep pattern even in these extreme climates. And the reason is it only works with both a natural light environment, a circadian eating pattern, and a work schedule flexible enough to accommodate sleeping on-demand.

Luckily, most new parents get time off to be with their babies, making postpartum the perfect time to experiment with polyphasic sleep and natural light. For me, it has been an absolute game-changer. I shared about this in my class The Surprising Good News and Sleep Interruptions in Motherhood.

And my new workshop about creating a Circadian Babyhood experience dives more into both the science and the practical aspects of this (exclusive for paid subscribers, so upgrade or request a scholarship if you haven’t already!):

And I’m alway happy to work with you in the community chat or in a 1-1.

1. Wehr T. A. (1992). In short photoperiods, human sleep is biphasic. Journal of sleep research, 1(2), 103–107. https://doi.org/10.1111/j.1365-2869.1992.tb00019.x