Simanaitis Says

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“5 Interesting Facts (and Myths) About Sleep,” at the Interesting Facts website described that medieval peasants slept better than we do.  (Artificial light makes sleep less natural today.) In giving this further research, I came upon Zaria Gorvett’s “The Forgotten Medieval Habit of ‘Two Sleeps,’ ” BBC Future, January 9, 2022. Here are tidbits from these articles together with my usual Internet sleuthing on what’s called, naturally enough, biphasic sleep. 

Enclosure of this four-post bed was more for conserving warmth than for blocking illumination. Almany image from BBC Future. 

Medieval Slumber. Interesting Facts writes, “In medieval Europe, there were no glowing smartphones or bedside lamps. At sundown, families blew out a candle and retreated to soft heaps of rags in one room. After about four hours of sleep, at midnight, adults awoke for a blissful hour or two of prayer, sex, reading, writing, or chatting, before they dozed off and awoke at dawn.” 

Modern scholars recognized this habit in medieval references to “first sleep,” implying that a “second sleep” must follow. For example, in Chaucer’s The Canterbury Tales, “The Squire’s Tale” describes Canacee, “ful mesurable [moderate], as wommen be… slepte hir firste sleepe, and thanne awook;” This, followed by “Lightly for to pleye and walke on foote,/ Nat but with fyve or sixe of her meynee [retinue];/ And in a trench [path] forth in the park gooth she.”

Zaria Gorvett notes, “The practice even made it into ballads, such as “Old Robin of Portingale.” “And at the wakening of your first sleepe,/ You shall have a hot drink made,/ And at the wakening of your next sleepe, /Your sorrows will have a slake….”

“In the Middle Ages,” Gorvett says, “communal sleeping was entirely normal—travellers who had just met would share the same bed, as would masters and their servants.”

Image from the British Library in BBC Future.

Gorvett continues, “Biphasic sleep was not unique to England, either—it was widely practised throughout the preindustrial world. In France, the initial sleep was the ‘premier somme;’ in Italy, it was “primo sonno.’ In fact, [historian Professor Roger] Eckirch found evidence of the habit in locations as distant as Africa, South and Southeast Asia, Australia, South America and the Middle East.”

These Days… Er… Nights. Interesting Facts observes, “That’s apparently the natural rhythm. In an experiment in the 1990s, in which participants lived away from artificial light, after three weeks they gradually drifted into the pre-artificial light pattern of waking in the middle of the night. Tests of their blood in the interlude showed that even without sex, they were awash in prolactin, a hormone released after orgasm that gives us the ‘afterglow.’ ”

Prolactin. This got me researching prolactin, the etymology of which suggests “in favor of milk production.” But also the NIH National Library of Medicine notes, “Research indicates that prolactin increases following orgasm are involved in a feedback loop that serves to decrease arousal through inhibitory central dopaminergic and probably peripheral processes. The magnitude of post-orgasmic prolactin increase is thus a neurohormonal index of sexual satiety.”

Sans Electricity. Gorvett writes, “Back in 2015, together with collaborators from a number of other universities, [sleep researcher Professor David] Samson recruited local volunteers from the remote community of Manadena in northeastern Madagascar for a study. The location is a large village that backs on to a national park—and there is no infrastructure for electricity, so nights are almost as dark as they would have been for millennia.”

Gorvett continues, “The participants, who were mostly farmers, were asked to wear an ‘actimeter’—a sophisticated activity-sensing device that can be used to track sleep cycles—for 10 days, to track their sleep patterns.”

Sans artificial light, the participants experienced “a period of activity right after midnight until about 01:00-01:30 in the morning, and then drop back to sleep and to inactivity until they woke up at 06:00, usually coinciding with the rising of the Sun.”

“As it turns out,” Gorvett says, “biphasic sleep never vanished entirely—it lives on in pockets of the world today.”

Like when I awake at 1 a.m. with a neat finesse to a GMax airplane project. Then I return to bed until BBC World Service’s 6:00 a.m. Pacific. ds 

© Dennis Simanaitis,, 2023 


  1. Andrew G.
    April 14, 2023

    An interesting post; thank you, Dennis. I recall reading the peasantry relied on these midnight intermissions to check for predators.

    Then there’s another form of polyphasic sleep, the siesta — take a couple of hours off after lunch, and work until evening. The first year I was stationed in Sicily, I presumed the locals were crazy. By the second year, I thought Americans were pazzi.

  2. Mike B
    April 16, 2023

    It might be that we naturally go through a wakeful cycle a few hours after going to sleep, whenever that happens,when nearly anything will wake us up. Some of us anyway. I was always the one to do the wee-hours tour with the baby; nothing would wake my wife, but I always was a light sleeper.

    These days, it’s common for me to get in a half-hour or so of reading or writing around 2-3 AM. In pre-electricity (or at least pre-everybody-leaves-outdoor-lights-on-all-night) times, that would be closer to midnight. Of course, how can you go to sleep before Colbert (which I always put the TV shutoff timer on for, since he invariably puts me to sleep)?

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