Previously I’ve written about segmented sleep. It seems that in olden times, before the advent of artificial lighting, human beings typically went to sleep soon after sunset, and slept in two shifts—"first sleep" and "second sleep"—with a period of waking in between. Our ancestors welcomed that mid-night waking period, known as "the nightwatch" as a time to stoke the fire, check on children or animals, pray, meditate, make love, or gaze at the stars. This “segmented” pattern of sleep was considered normal, natural, and pleasurable. It can still be observed in many other mammalian species, and in humans living in pre-industrial societies.
Roger Ekirch is a professor of history at Virginia Tech and the author of "At Day's Close: Night in Times Past." His writings have helped me form my own ideas and opinions about sleep and society. The New York Times recently ran a brief, eloquent piece of his entitled Dreams Deferred, well worth reading, in which he sheds new light on the historical phenomenon of segmented sleep. He has an interesting story to tell.
Ekirch feels that, contrary to much of the current wisdom on the near universality of insomnia and sleep deprivation (and which, incidentally, is in part fueled by a pharmaceutical industry intent on marketing drugs to those sleep deprived masses), we really are enjoying a kind of Golden Age of sleep right now. True, the advent of artificial lighting, television, and computers, plus the scheduling demands of modern industry, have shortened our hours of sleep considerably. But Ekirch believes that the quality of our sleep is probably better than ever before. He cites the prevalence of lice, noxious chamber pots, and tempestuous weather, as well as untreatable, chronic respiratory illnesses like influenza, pulmonary tuberculosis and asthma, as factors likely to have kept our forebears tossing and turning on their beds of straw and listlessly dragging their knuckles through the countless eons prior to the advent of double-hung windows, Tempur-Pedic mattresses, and penicillin.
Curiously, to my mind, Ekirch cites segmented or "broken" sleep as another factor contributing to poor sleep quality in former times. That's odd, especially since almost all the contemporary accounts he cites seems to sing the praises of this slower, more leisurely sleep pattern. For example, he cites a 16th-century doctor who lauds the nightwatch as the best time for sexual intimacy, because the well rested couples have "more enjoyment" and "do it better.” And he cites the 17th-century moralist Francis Quarles, who urged his readers to “Let the end of thy first sleep raise thee from thy repose: then hath the body the best temper; then hath thy soul the least encumbrance.” That hardly sounds like the raving of a cranky insomniac, does it?
Furthermore, I haven't seen any evidence indicating that dividing a night's sleep into two segments with an hour of quiet wakefulness in between does anything to detract from the quality of sleep, and I suspect there isn't any. Segmented sleep presents a problem only when there is a strict limitation on the number of hours available for nightly rest. If you need eight hours sleep and you've only got eight hours (or less!) in which to get them, then you'd darn well better go to sleep on time and stay that way until the alarm clock jumps off the nightstand. Under those circumstances, sleep is as rigidly regimented as any production line, and any interruption of those precious hours is going to be cause for great frustration and disappointment, emotions which are themselves bound to produce excess arousal delaying the return to sleep. But if instead you turned in at eight or eight thirty, not long after sundown, and were at your ease until sunrise at five-thirty or six in the morning, that would give you a good nine or nine and a half hours in which to go gentle into that good first half of the night, awaken for a self-nurturing hour of meditation, sex, or astronomy and, finally, to savor a deep, dream-dappled second sleep 'til the cock crowed.
As if to further undermine his own argument, Ekirch cites some fascinating research conducted at the National Institute of Mental Health, previously unknown to me, in which human subjects deprived of nighttime illumination exhibited just that pattern of segmented sleep that is suggested by the historical sources. The research found that during their periods of wakefulness these subject secreted significantly higher levels of prolactin, “the same hormone that allows hens to sit happily on their eggs for long periods.” Ekirch, or perhaps it was the researchers themselves, speculates that those higher prolactin levels probably explain the feelings of peace and complacency associated with “first waking” in the historical sources, and that prolactin is what makes the difference between a storm tossed night of insomnia and the “non-anxious wakefulness” typifying the nightwatch.
Setting these quibbles aside, there is still much to recommend Ekirch’s article and his book. To his great credit, he cites Dr. Thomas Wehr, the scientist who conducted the NIMH experiments, opining that “some common sleep disorders may nothing more than sleep’s older, primal pattern trying to assert itself—‘breaking through,’ as Dr. Wehr has put it, into today’s “artificial world.” What a blessing to hear this from someone else’s lips, for this is exactly what I have been saying to anyone who would listen for several years now. In that case, the most effective course of therapy is simply to allow more time in that busy schedule of yours for introspection, contemplation, rest, relaxation, and sleep, sleep, sleep.