Until a few hundred years ago, your ancestors went to bed shortly after dark, slept for four hours, woke for an hour or two, then went back to bed for a “second sleep.” This pattern was the norm throughout much …
Until a few hundred years ago, your ancestors went to bed shortly after dark, slept for four hours, woke for an hour or two, then went back to bed for a “second sleep.” This pattern was the norm throughout much …