西德马普学会精神病研究所的科学家经过研究发现,每个人在夜里睡眠之后,白天又会出现几个阶段的睡意,大约每4个小时发困一次。困倦在中午最为明显,而在上午9点和下午7点却不太明显。最困乏的时间是在夜间睡眠一半时间之后的12个小时出现,如从午夜睡到早晨6点的人,到15点时就有一种睡眠的生理需要。许多调查表明,午睡具有积极作用,午睡后, Scientists at the Institute of Psychiatry at the Western Max Institute found that after sleep in the night, sleep retardation occurs in several phases during the day and sleeps about every 4 hours. Drowsiness is most pronounced at noon, but less pronounced at 9 am and 7 pm. The most sleepy time is 12 hours after half-night sleep occurs, such as those who sleep from midnight to 6 am and have a physiological need for sleep by 15 o’clock. Many surveys show that nap has a positive effect, after a nap,