It’s no secret that every person has their own rhythm and to define it simply. If your body in the morning is hard to cope with the awakening and hours vigorous activity accounted for an evening or night, you – a night owl. "Larks" contrary adapted to rise almost with the dawn, and immediately take up the case.

Before the modern era, the sounds of nature were everywhere, day and night. Buildings, even medieval castles with walls thick enough to resist sieges, were not constructed to keep them out.