The first thing to figure out how much time you need to sleep. On average, a person needs for a healthy sleep about 8 hours. But every body is different, and each load is also different.
Since you are likely to know how much you need to wake up, then you will easily determine at what time you will need to go to bed. If you need to get up at 8:00, then at 12 o'clock in the morning you should already lay with his eyes closed, and ideally sleep. It is desirable to put such an experiment over the weekend when you can safely get up without an alarm clock.
If you wake up before 8, it means that your body requires less time to recover. Can sleep in the next day so minutes later, as before you get up.
If the situation is reversed, then go to bed earlier for the same amount of time.
It is worth remembering that quality sleep should be deep and continuous. Even if you get some sleep for 2 hours less than normal deep sleep, it will be better than sleeping put 7-8 hours sleep restless, in which you will often wake up. In this case, you will be "doze off" in the middle of the day. Deep sleep is enough to maintain the optimum temperature in the room, about 17 degrees.
You also need to know that you should not change the sleep schedule. Even if the next day Sunday and you do not work - go and get up as usual. In the habit of the body, and you can then get up at all without an alarm clock. And what could be more beautiful than the morning when you wake up on their own, full of strength and energy?
How many hours of sleep for sure, scientists still argue. Someone leans that exactly 8 and no more, no less. Someone just as adamant about 7 hours. All just agree that regular sleep too long (over 10 hours), as well as too short (less than 7:00), is bad for health. Subsequently, the disease may occur cardiovascular system, as well as increases the likelihood of premature death.