First and second sleep.
Intriguingly the practice of going to bed in the late evening and staying there until rising the next morning appears to be a recent innovation.
Research by Roger Ekirch has highlighted how pre-industrial societies typically adopted split sleep patterns.
Despite some controversy the historical consensus now accepts Ekirch’s findings that pre industrial humans split their sleep into two segments.
In England this took the pattern of a “first sleep” from nightfall to around midnight. There was then a waking period or “watch” of a couple of hours. The watch is variously recorded as being used for sex, eating, socialising, taking medication and thieving. In truth the way in which the watch was used will have varied over time, geography and doubtless between individuals. After the watch cam the “second” or “morning” sleep starting at around 2am. This was usually the more substantial period of sleep lasting at least until dawn.
America at least prior to the eighteenth century seems to have followed a similar sleep discipline to the English pattern described above.
So is biphasic sleep- to give it its scientific name more natural. Possibly? Mediterreanean societies with their siestas still follow a similar pattern- although the sleep portions at a very different time.
And why did western societies move from biphasic to monophasic sleep during the eighteenth century. Industrialisation with its monolithic work patterns undoubtedly played a role. It’s difficult to fit into two sleeps if you need to be at work for 6am. But split sleeping ended in rural as well as industrial communities.
The introduction of electric light has been identified as a causal factor. But this seems unlikely. Electricity became common place in the last two decades of the nineteenth century, roughly 70-80 years after first and second sleeps had been ditched by most people. Equally wouldn’t electric light make split sleeping more rather than less practical?
Standardised time on the back of railway timetables possibly played a role too. But again the chronology doesn’t really work with this only gaining traction from 1850.
Is biphasic sleeping hard wired into our DNA? And crucially could it provide a route out of insomnia for at least some sufferers? There is virtually no research testing this hypothesis. Anecdotally Mediterranean populations with their siestas do seem to have lower levels of insomnia- but multiple factors including diet and greater social connectivity could be at play here.
With insomnia and chronic poor sleep there is no one solution. Sufferers need to try a range of approaches to try and find what works for them. We think our 3 point sleep plan is excellent- but it’s success rate is only 38%!
So, if your sleep is poor and you are in a position to incorporate biphasic sleeping into your life, then it might just be worth giving it a go. We would recommend that you try it consistently over a period of a month or so. And try and stick to the same schedule every day.