Should we go back to sleeping twice a night?

Anthropologists have found evidence that during preindustrial Europe, bi-modal sleeping was considered the norm. Sleep onset was determined not by a set bedtime, but by whether there were things to do. Historian A. Roger Ekirch’s book At day’s close: night in times past describes how households at this time retired a couple of hours after dusk, woke a few hours later for one to two hours, and then had a second sleep until dawn.

During this waking period, people would relax, ponder their dreams or have sex. Some would engage in activities like sewing, chopping wood or reading, relying on the light of the moon or oil lamps.

Ekirch found references to the first and second sleep started to disappear during the late 17th century. This is thought to have started in the upper classes in Northern Europe and filtered down to the rest of Western society over the next 200 years.