Technique behind gettin up early

Various changes occur in the body day and night. These changes are cyclical and occur periodically is called 'circadian rythm'. The technique behind getting up early is to set alarm in the biological clock which is in our body. It has been found by the medical units that these changes occuring periodicaly and cyclic are controlled by a center called "suprachiasmatic nuclei" in hypothamus.
This place in the brain secretes a hermone called ACTH(adreno cortic trophic harmone) whose level in the body fluctuates during day and night but in cyclic manner. Thus the level is min at night (during sleep) and max just before awakening. When there is increase in secretion of epinephrine & nore pinephrine. One of the effect of this mous sympathetic discharge is reinforcement of alert alternative state necessary for effective action causing awake.
By setting up early for a week we do allow the raise in level of ACTH to occur early at that time in the morning. Next day, ACTH level raises automatically at the same time early in the morning. By which we are able to wake up even if we dont keep an alarm in a clock, see that we get exactly at that same time.