Second Sleep - Are We Resting Wrong?

David Trammel's picture

I've been seeing a few studies recently on sleep, which look at our "typical" modern pattern of trying for one continuous 6-8 hour rest cycle and how that may be an outlier and not typical of all the rest of human history. There is a recognition that in some medieval writings, there was two periods of evening rest, a "first" sleep and a "second".

First sleep was started early in the evening not long after the Sun went down, probably to conserve lighting sources like oil and candle. Then sometime around midnight, people would wake for a period of a few hours before they would retire and sleep until just before dawn. I have my theory that this midnight waking might be tied to the need to tend the fire, or in dangerous situations, to change the watch of guardians. Its beginning to seem that the hundreds of thousands of years that our forebears and ancestors did this may have bred us to be more healthy if we did this now.

"Can Medieval Sleeping Habits Fix America’s Insomnia?"

Personally, I've ended up with a habit of 5-6 hours of evening sleep, going to bed around 9pm and rising at 3am for work, and then a second sleep of a 1-2 hour nap once I get home, from 11am to 1pm, but that's not what this seems to be.

Do you nap or split your sleep?

Ken's picture

The topic of this article interests me, though I must admit that the excessively witty, urban 'style' that is so prevalent in the Atlantic is really annoying to read. Perhaps I'm just cranky from not enough sleep? Or perhaps it's because as I near my sixties I am less physically exhausted at the end of the day. Don't get me wrong; I'm TIRED, but sometimes not muscularly, more mentally fatigued. And on those nights I sometimes wake in the wee hours, so called because that's when you get up to take a wee, right? ;-) Instead of fighting it, I will get up and journal on paper until I start to feel sleepy again, which is typically around dawn. If I use the computer, even with blue-blocker glasses (which I always wear when using any screen) I'll be up for the day and crashing in mid-afternoon. I'd heard of the 'two-sleep' notion from a friend but I didn't find it particularly compelling the way she described it. I thought this article might have more substance, but no.

I DO think that there is an evolutionary explanation for a wide and weird number of human traits and that having certain periods of our lives be prone to not sleeping very long at a time, could have some serious advantages collectively. For virtually all of the history of our species on the planet, and presuming you count Home erectus, that is likely in the neighborhood of 2,000,000 years, all of which time we lived in small, tribal/extended family groups with fire as our greatest technological innovation.

Which brings me to tending the fire and keeping watch for predators/enemies. Teenagers have notoriously weird sleeping habits and are frequently most energized at night, which could be darn handy for a group trying to sleep but needing to keep a fire lit at the cave mouth to keep the lions and hyenas away! And to simply keep the fire going; which was undoubtedly essential for many thousands of years until someone figured out how to start a fire from scratch; just imagine THAT transformation!

Somewhat similarly with the elderly, though we aren't up in the night because of hormones and excess energy, we're just too sore to lay there any longer! Regardless of the cause, the effect of having a few members of the tribe awake at all times to keep the fire burning, was undoubtedly so advantageous to the survival and reproduction of the group that despite possible disadvantages to the individuals, it became a trait or tendency that was ruthlessly selected for.

So, David, your comment about tending the fire and changing the guard was, I think, absolutely right on.

ClareBroommaker's picture

Well, I did not even skim over the article, but searched on every term I could think of relative to breast feeding an infant. An article that talks about evolutionary sleep habits without addressing how a woman's sleep is interrupted every single night, multiple times, just to keep alive a new generation is missing a big chunk.

Every woman who nursed her children will have stories of sleep deprivation. I'll only say that it was for several months that I had to awaken every two hours to nurse, and that took forty minutes. That means I got sleep in 1 hour, 20 minute episodes. Dear god!-- if I had to stoke the fire or finish daytime chores during the night as well!

Ken's picture

Thank you for the reminder that most theory and research has been done by men and almost inevitably focuses on life from a male point of view. I am chagrined that nursing mothers never crossed my mind when thinking about our ancestors keeping the fire going... Mea culpa.

My own two daughters were breastfed but obviously not by me. Despite all the well meant advice about getting up and nursing, we just slept with the baby in the bed with us. We all got less sleep than before but we were young and both the girls were pretty easy babies. I can't imagine the sleep chaos of a colicky baby...