It is not sufficient that these eight hours should be taken at any time of the day or night that happens to be convenient. The old idea of “beauty sleep” is perfectly correct, for there is no rest equal to that obtained during the first part of the night, and no amount of lying in bed in the morning can make up for the loss of it.
Ask anyone who has to work at night, nurses, doctors or workmen on night shift, and they will tell you without any hesitation that such work takes twice as much out of them as a corresponding amount by day. They will also declare, if you inquire further, that the sleep they get in the daytime is not half so refreshing as that obtained during the night.
Human strength ebbs and flows with the regularity of the tides, with the difference that the rise and fall occurs once instead of twice in the twenty-four hours. The system is at its best from about six in the morning until the evening. It is at its worst from about eleven at night until four in the morning, and during those hours, if people are awake, either at work or at play, and even if they have had abundance of sleep during the course of the day, the heart tends to flag, and all the powers and faculties are lowered. It is on that account that people who have to sit up all night begin to feel chilly and tired in the dead of night, even though the room itself may be quite warm. They feel cold and uncomfortable, simply because their whole systems are depressed. It is for the same reason that people who are ill are almost always worse during these hours.
To sit up night after night, even with plenty of rest in the daytime, is wearing to the system. To do it without that daily rest would speedily cause a collapse. And people who habitually sit up later than they should do, not going to bed until midnight or after, are in danger of bringing about the same catastrophe, only in a slower manner. There is a measure of excitement about these late hours which makes them alluring. Many people say that they can work or write more easily or play cards with greater zest then than at any other time, but it is a false form of stimulant, for which the system has to pay a heavy price later on.
Regular and early hours are essential to health, and the neglect of them is often the means of starting a breakdown, or bringing it to a head. Many cases of insomnia are due to a want of punctuality in this respect. And of all the tortures with which mankind can be afflicted there is none worse than insomnia, and none that so surely undermines the nervous system. One of the most vital points in the prevention of breakdowns is to consider the different ways in which sleep can be obtained--and to carry them out.