Sleep: A Revisionist Perspective
"Throughout the ages, humans have regulated their sleep according to their working lives. Five centuries ago Britons enjoyed something known as 'fyrste slepe', an early evening nap. Supper usually followed, then a period of prayer or talking. People would then stay awake until the early hours of the morning, then had a five to six-hour sleep.
"'It seems to me that a night of between seven and eight hours' sleep is a fairly modern western development, which is clearly linked to industrialisation,' said Horne. 'Human beings are very adaptable, and we should keep that in mind because we tend to think of these hours as sacrosanct, when in fact we are far more flexible than we like to think.'"
"The phrase 'hangover' does not come from some alcohol-related source but from the bedtime tradition in Victorian workhouses. Workers lined up along a bench and a rope was tied from one end to the other, allowing them to sleep by draping their arms over the rope which they 'hung over' as it supported them."