Circadiana: Everything You Always Wanted To Know About Sleep (But Were Too Afraid To Ask) opens with this summary of human sleep (and sleep research):
Until not long ago, just about until electricity became ubiquitous, humans used to have a sleep pattern quite different from what we consider “normal” today. At dusk you go to sleep, at some point in the middle of the night you wake up for an hour or two, then fall asleep again until dawn. Thus there are two events of falling asleep and two events of waking up every night (plus, perhaps, a short nap in the afternoon). As indigenous people today, as well as people in non-electrified rural areas of the world, still follow this pattern, it is likely that our ancestors did, too.The bimodal sleep pattern was first seen in laboratory animals (various birds, lizards and mammals) in the 1950s, 60s and 70s, i.e, before everyone moved their research to mice and rats who have erratic (un-consolidated) sleep patterns. The research on humans kept in constant conditions, as well as field work in primitive communities (including non-electrified rural places in what is otherwise considered the First World) confirmed the bimodality of sleep in humans, particularly in winter.An excellent quote from Robert Heinlein:
Waking a person unnecessarily should not be considered a capital crime. For a first offense, that is.This is so true:
The “owls” are constantly being treated as lazy, though they are more likely to be sleep-deprived (cannot fall asleep until the wee hours, then being rudely awoken by the alarm clock after just a couple of hours) and spend more hours awake (and presumably productive) than “larks” do. If you are asleep, this means you need it.I didn’t realize these accidents were sleep-related:
People have always tried to self-select for various schedules, yet it has recently started to enter the corporate consciousness that forcing employees into unwanted shifts has negative effects on productivity and safety, thus bottom line. See Chernobyl, Bhopal, Exxon Valdese and Three Mile Island accidents — all caused by sober but sleepy people at about 3am, just like thousands of traffic accidents every year.