It is worth remembering that before artificial lighting the normal sleep pattern is to sleep in two segments and get up in the middle to have sex, talk, do some chores, change the baby etc. And I believe a normal sleep cycle is something like 90 minutes so if you *really* sleep in 3 hour chunks that's actually probably healthier than the normal us sleep schedule. I mean many of us find the usual wake at 7am alarm schedule to be pretty damn brutal. However, if what you actually do is kinda lie around check your phone in bed etc and then get blasted awake by an alarm that's a different story.