When you examine the sleep and wake up hours of people around, you will see that some of them tend to sleep early and wake up early; while the others tend to sleep late and wake up late. This tendency - which can not be observed in weekdays due to the obligations of social life – can be observed clearly at weekends as then, there is not any obligation to sleep and wake up at certain hours. It is know that; sleep and wake up hours are also genetically determined so as the sleep duration
Morning types sleep early in the evenings even at holiday and the following day they wake up early although they are not obliged to do so.
Evening types do not sleep on Saturdays until the late hours; and Sundays they sleep until noon. At intensive days like examination periods, morning types prefer to wake up early and work; while evening types prefer to work staying awake until late hours of nights.
The characteristics of morning and evening types are reflected in our daily lives more indirectly. Evening types have difficulty at waking up in the morning and they drink a couple of tea or coffee in the mornings in order to start to work and they start to be productive in their work only towards the afternoon hours. Unlike evening types, morning types work more efficient in the mornings and their efficiency is reduced when they work at the night shift.
As I previously mentioned, our daily sleep necessity is genetically determined. Sleeping at daytime may reduce night sleep hours. It is recommended to sleep daytime sleep at 02.00 p.m as then it is easier to fell asleep. A half-hour daytime sleep –which is mainly consisted of deep slow sleep phase – is equivalent to a 1,5 hour night sleep. Therefore, sleeping half an hour in daytime may reduce 1.5 hour of night sleep. Sleep intensity –i.e.falling asleep time – increases in proportion to the time spent awake and it reduces the following start of sleeping. Naps cause reduction on sleep intensity and reaching to intensive levels may be reached in later hours. This may allow us to stay awake until late hours at nights.
It is known that; if we nap around 02.00 p.m –which is considered relatively inefficient hour and we have more tendency to sleep - , it makes us more energetic during the remaining hours of the day and it makes us sleep later and less. Nap has become traditional in the warm climate zone; and also some politicians and well-known people from the business and the science community take nap at noon. In this regard, there is a very surprising practice in Japan. Some companies in Japan pay additional salary to their personnel who take nap at noon and therefore they support their employees to take nap at noon. Is it possible to live without sleeping?
Sleep is an indispensable necessity for the organism just like eating, drinking water, breathing etc. It is not possible to live without sleeping just as it is not possible to live without eating or drinking water. When people left sleepless for experimental purposes, the emperiment can usually continue 3-4 days; because experiment subjects fall asleep involuntarily for a short time. When sleepless time is prolonged, it is observed that; sleep attacks become more frequent and longer.
In sleep deprivation experiments, at the end of the third day it is observed some sytoms such as tension, nervousness, not knowing the time, day dreaming, stuttering, inability to understand spoken issues etc.
The longest sleep deprivation experiment performed so far was carried out on an American college student and it lasted 11 days. The experiment was finished when it is observed that the experiment subject student’s relation with reality was deterioried and he was enterion to a clinic condition similar to psychosis.
Similar experiments with animals were resulted with death of the experiment subject animal in various times depending on the animal’s kind.