Human beings spend about one third of their life sleeping. But the place of sleep in the life of human beings is not restricted to this time; the quality of a person’s sleep also affects the waking hours. Moreover, the growth hormone secreted during sleep plays an essential role in the development of children. On the other hand, other functionary hormones are employed in the care, restoration, and refreshment of the body.

CAN A PERSON LIVE WITHOUT SLEEP?
Sleep is known as one of the basic needs that are necessary to sustain life in addition to eating, drinking, and respiration. There have been some studies about the endurance of people to sleeplessness. The period that a normal person can do without sleep is three or four days on average. At the end of this period, some problems arise such as absent-mindedness, irritability, not knowing the time, hallucinations, stammering, not understanding what is said, trembling of the hands, inflammation in the body, pain, and defective vision. The longest one of these experiments was carried out on an American undergraduate student. After 11 days of sleeplessness, the experiment was ended when his health was under serious threat.

HOW MUCH SLEEP DOES A HEALTHY PERSON NEED?
Various studies on sleep show that the period of sleep we need for a healthy and balanced life is between 4-10 hours for an average person, depending on genetic factors. It is about 6-8 hours for adults.
On the other hand there are some studies that show that we do not have to sleep eight hours a day, on the contrary six, five, even four hours can be sufficient.

WHAT ARE THE CONSEQUENCES OF TOO MUCH OR TOO LITTLE SLEEP?
Those who sleep too much or very little tend to face health problems as compared to those who enjoy regular sleep. In a long-term study, more than 71,000 women were observed over ten years and two important points were determined: firstly, long hours of sleep increased the risk of heart disease; secondly, those who slept too much faced as many health problems as those who slept very little. Sleeping too much can cause obesity, diabetes, high blood pressure, a decrease in muscle volume, a reduction in the immune system function, and depression.

WHAT KIND OF RELATIONSHIP IS THERE BETWEEN THE AMOUNT OF SLEEP AND REST?
We can see in our own experiences and that of others that there is no direct proportion between the amount we sleep and the amount we rest. A person who sleeps little can feel rested more than one who sleeps too much; the former one has had a restful sleep that is sufficient.

WHAT SHOULD BE DONE TO ENJOY QUALITY SLEEP?
There are some important points in daily life and prior to sleeping that need to be focused on:
- One should have a light meal in the evening, at least two hours before sleeping. Heavy meals carry risks for those who have problems with snoring and respiration. Drinks that have stimulating effect, such as tea, coffee, and cola delay sleeping.
- The sleeping atmosphere is important.
The ideal atmosphere for quality sleep requires low light, quiet, and a warm room with a bed which is not too hard or too soft.
- One should have a regular sleeping habit. One of the conditions for enjoying quality sleep is to sleep and wake up at the same hours. It is particularly important to have regular sleep on week days. The disruption of this regularity at the weekend is one of the stumbling blocks standing in the way of a quality sleep.

- One should lie on the right or left side. Lying flat on one’s back or lying prone can bring certain problems. Snoring or interruption of respiration only occurs while lying flat on one’s back. The most suitable position for sleeping is to turning to the right or left.
A person unconsciously moves and changes position 10 or 15 times during his sleep

DURING WHICH HOURS SHOULD
WE SLEEP?
We should know that the pineal gland is installed in the human body as a system to secrete certain hormones. One of them is melatonin hormone which regulates the cycle of sleep and waking. The secretion of melatonin begins in the evening and goes on until it peaks at two or three o’clock. That means a system was innately installed in the human body that makes sleeping easy in the evenings. On the other hand, being exposed to extreme artificial light, watching television at midnight, and external effects, such as electromagnetic fields, decrease the production of melatonin and is harmful to the running of the system. There are also some facts about napping. The best time for a nap is midday according to the experts. A half-hour siesta consisting of a deep and slow period is equal to two hours of nighttime sleep. Therefore when one sleeps at midday, they will need less sleep at night.

In brief, the “sleep” is a great bounty for human beings. However as with all bounties, it is important to find the middle course in sleeping if we want to live a healthy life and to benefit from this during the recommended hours and in the recommended ways.