Two main schedule types have been practiced by humans since time immemorial: [[Special:MyLanguage/Segmented|Segmented]] -- with two long sleep in the night separated by a wake gap, and [[Special:MyLanguage/Siesta|Siesta]] -- one long sleep in the night and a shorter sleep in the afternoon. Of course, the schedule timings of the ancient people are more flexible and thus likely contains more total sleep than the current standard ones. Most current polyphasic sleep schedules evolve from monophasic sleep as well as the above two historically common schedules.
自古以来，人类遵循的时程主要有两种：晚上有两个长的睡眠，中间有一个醒来的间隙的分割睡眠，以及晚上一个长的睡眠，下午一个短的睡眠的Siesta。当然，古人的时程安排更加灵活，因此很可能比目前的标准时程有更长的总睡眠时间。目前大多数多相睡眠时程都是从单相睡眠以及上述两种历史上常见的时程演变而来的。
