Common truth as it may seem – sleep 8 hours minimum every day, keep regular hours, still not following these rules will seriously decrease mental productivity and damage immune system. How much does our productivity depend upon good and regular sleep? How many hours of sleep is enough?

Scientists from University of Pennsylvania and University of Washington State organized series of experiments, during which 48 healthy men and 1 woman firstly slept for 7-8 hours. Then group of volunteers did not sleep for three days, other group slept for 4 hours per day, third group slept for 6 hours, and the luckiest was the fourth group with its members sleeping 8 hours per day.

After two days of experiment, people underwent tests for mental and physical productivity. Surely best results showed those who continued sleeping for 8 hours per day – they approved the level, shown before experiment. Results of those who slept for 4-6 hours were worse and were getting lower day by day. Even worse – in a week, every fourth member of sleep debt groups started falling asleep suddenly in any unexpected place. There was no substantial difference between those participants sleeping 4 hours and 6 hours. Even more – in two weeks their results were almost equally low.

Worth mentioning the fact that participants of experiment did not notice lowering of their productivity, they considered themselves very successful and were proud of their efficiency. From the outside, those participants looked quite different… Looks familiar, isn’t it?

So all scientists agree in one point: 95% of adult people need from 7 to 9 hours of good sleep every day. Children and elderly people need plus one more. In addition, it is better to go to bed at regular hours, and it is necessary to provide good conditions for both phases of sleep: the deep one, recovering a body, and the surface sleep, when we see dreams and even movements of eyeballs under eyelids is visible to others.

Great effect of a deep sleep is obvious: a body is resting; immune system is recovering, muscles gain back their elasticity, spine straightens. Nevertheless, if you need success in intellectual field or fast response of a sportsmen – surface sleep is also vital important, for during this phase our brains systematize information, neurons are growing.

There should be not less than five interchanges of slow (deep) and quick (surface) phases of sleep during one night. Moreover, in the crucial days, for example before enter tests; one should sleep for ten hours. For instance, basketball players usually sleep for 8 hours, and before competitions, they sleep for 10 hours to guarantee precision of throws and fastness of response. Lebron James and Roger Federer have a 8 hours’ sleep every day and before competitions sleep for 11-12 hours per day.

What can be done if though schedule does not allow finding eight necessary hours for sleep every day? Pupils can nap in the daytime at least 20-30 minutes (preferably for an hour). Right upon awakening you will have excellent response, fresh mind, and readiness to memorize many different data. In this case, preparation via online lectures is a very useful option: one can have a dinner after school, nap a bit, and then start studying. Viewing online lecture, answering questions, making tasks and passing tests will be performed in one’s own pace, with profit to health and with good learning results.