It's not the first time I hear about this — i.e. the book "Centuries of Childhood" by Philippe Ariès writes a bit about mentions of this habit in literature. If

It's not the first time I hear about this — i.e. the book "Centuries of Childhood" by Philippe Ariès writes a bit about mentions of this habit in literature. If I remember correctly (which I may not), it mentions it was common for some period, but neither before or after. In general I'd wish if people were more careful with general pronouncements like this — just because some people somewhere did something (say, hunt by running, eat only meat, eat only berries, sleep in two parts, sleep with the head hanging down, bake crackers, not cook anything, whatever) doesn't mean all humans did that until 5 years ago, nor does it mean it's a somehow best course for every single human dead or alive. Now, that it may be a good idea to try out (depending on specific idea, with specialist supervision maybe), but it might turn out horrible. And I doubt anything like "optimal" sleep even exists, unless you start including additional conditions. You need work, you have to balance the need to sleep with the requirements of it (and some enjoyable jobs do start early), you might even a tendency to sleep too long for own comfort unless kept in check, and if you have apnea sleeping longer will only make things worse. So, my annoyance here is mostly with the generalization made by the statement — not "we". Some other people, at some point in history, did, and wrote down all the awesome experiences they had while doing it.