It occurred to me last night, as I got home from work only a few minutes before midnight, how “midnight” seems to be anything but, these days. I very rarely, maybe one or two nights a month, go to sleep before midnight. I don’t think I know anyone whose sleeping hours are more than 25% “before midnight”.
These days, of course, that stnads to reason. We have stuff to do long into the evening, we have electric light, and most of us don’t have to be in work until 8.30 or 9am (not till 10.30am in my case!). Also, Daylight Saving Time shifts midnight forward in the day during summer, so that at my latitude at this time of year, it’s still fairly light at 10pm.
But was “midnight” once pretty much in the middle of people’s sleep time? That is, in the absence of modern distractions, would humans pretty much go to sleep when it got dark and wake up when it got light? Or was human nature always to sit around after dark drinking and chewing the fat?
I always figured it had more to do with it being in the middle of the hours of darkness- ie, approximately 6pm to 6am, give or take a couple of hours either side.
I’m told that until relatively recently, however, once it got dark, people basically went to bed, and woke up when it got light. No cite on that, though, but it’s certainly my understanding of the subject.
It used to be the case that time reckoning was based on Noon because it was comparatively easy to gauge when the sun crossed the meridian. For reasons that I don’t know for sure yet (maybe that will become clear during the course of this thread) 24 hours were used to subdivide the time between two successive noons. Whatever halfway really meant in terms of sleeping time or minimal activity it was halfway between noons.
Once it became common to have artificial lighting during the darkness hours, the hours for sleep adjusted to permit a later-than-sundown bedtime. Rising at dawn probably maintained its utility in agricultural settings but lost its significance in more urban settings.
Once occupations moved indoors to artificially lighted settings the notion of working during “daylight” hours became less a necessity and more a convention, so that shifts of labor became more the norm and this adjusted still further the tying of sleeping to some specific times of day.
I suspect you’d need to go back at least as far as the birth of the factory to get a starting point for these changes. That’s got to be over 100 years ago.
I just wanted to add that I know why it is midnight, being halfway between successive noons and (allowing for time-zone inaccuracy) and pretty much halfway between sunset and sunrise. I’m curious about whether people have always had a bias to stay up longer after sunset or whether we should “naturally” be sleeping from about 8pm to 4am. (For me, I would rather sleep from 2am to 10am… or perhaps from 6pm to 8pm and then again from 3am to 9am!)
The question about when humanity developed the desire to “stay up” after darkness had set in is one that probably goes back to campfires. How late they might stay up gabbing about the day’s hunt, or the need to get some sleep for the big hunt tomorrow, or to establish the tribe’s local backstory about ancestors and gods and such, more than likely varied by tribe or even individual. I imagine that variety exists to this day.
OK, so on a different angle - would it be better for us to sleep through the natural hours of darkness and wake up when it gets light? Is staying up till 1am in electric light, then sleeping till 8am and waking up to sunlight streaming through the curtains, bad for the bodyclock?
Background: I work four-day weeks and don’t see a great deal of daylight in that time. Typically I go to bed between 1am and 2am, wake up about 7.45, see an hour or two of daylight on the way to work, then spend 12 hours in an office with very little natural light. (OK I may go out for half an hour at lunchtime.) Then I leave about 10-10.30pm, by which time it is dark at all except a couple of weeks in midsummer and repeat the process. Thank Og for weekends!
In my own case I have worked shifts where “normal sleeping hours” were in the daylight hours. Except for the noises of the daytime I slept as well and as long as I did when I was on days working and nights sleeping.
I sincerely believe the issue is a personal one and that there probably isn’t a satisfactory “best for everybody” answer.
I imagine it could be, especially at the more extreme latitudes. I remember living in Anchorage where I could go weeks in the winter without ever seeing daylight, such as it was. Up at 8am (sun’s still down), work until 5pm (sun’s been down for hours). SAD can become a real problem. The body’s natural rhythm can be tweaked, but not that much!
Daytime averages 12 hours per day in length, plus a little twilight on either end. Most people are awake about 16 hours per day. So you see right away that complete synchronization of sleep time and darkness is impractical, save at mid-latitudes near the summer solstice.
But yes, in earlier times when most people lived via agriculture, hours of awakening were more centered around daylight. Outdoor farm work can only be done when it’s light, and one must adjust one’s work hours to the animals, who wake with the light. Even today farmers are known for going to bed early and getting up early, and they don’t like Daylight Savings Time.
Quite true, moonlight can be quite effective for some tasks. And really, many farms now have those new-fangled electric lights.
I’ve been driving on rural highways near midnight, and seen tractors with large headlights pulling cultivators or other equipment thru the fields. That’s quite common.