Firstly, Afternoon nap time should not be too long, had better within 1 hour:

  Physiology study indicate, human body sleep is two shallow sleep and deep sleep mark stage. Under normal conditions, people is falling asleep shift to deep sleep after 80 ~ 100 minutes, just gradually from shallow sleep. In the process of deep sleep, every neutral restraint process reinforces a cerebrum obviously , a lot of blood capillary net closes the brain for the time being in organization , brain blood rate of flow falls off , body's assimilation of the new and excretion of the old is horizontal obvious lessening.

  The blood capillary net being closed down can open to the outside world immediately neither , be bound to bring about one fault nature blood-supply deficiency appearing on cerebrum , if people wakes up suddenly in deep sleep stage since deeper restraint process can not remove immediately in the cerebral cortex,plant provisionality chaos appears on nervous system function , person understanding is felt to feel bad very much.
  That this indisposed feeling needs to continue for 30 minutes or so approximately is able to disappear gradually just now. It can be seen that afternoon nap time is not to the longer , the better, but respond to be suitable within 1 hour ,now that such being able to have an effect to remove strain, not to such an extent as to have slept deeply but no easy to wake up.

Senondly , Ought not to have a nap immediately after lunch;

  Sitting down or lying down immediately after meal , walk for last a moment and then. 30 minutes , many friends say , the afternoon nap is over , the head aches very much to had better to sleep only. Have slept to be over to want to sleep , have slept to ache, this is that are what head oxygen deficit brings about because of you sleep very long. Because after the lunch, stomach inner is full of the food digesting not yet,dropping to the ground immediately now may make person produce glutted feeling. Had eaten the lunch queen , first, have made some of slight activities , had waited if taking a walk, and then had had a nap after lunch again, such beneficial to the food digestion absorbs.

In addition, Need to be particular about sleep posture;

 Some people ,afternoon nap, sit to doze off on the chair or the sofa, some people bends over table to go ahead sleeping. In fact, these method of work is all incorrect. Muscle loosens the human body under sleep circumstances, pulses unexpected turn of events is slow , the blood vessel dilatation , blood pressure reduce, the blood flowing into a cerebrum falls off relatively. Especially after  the lunch time , more blood enter a stomach intestine, sleep now if being sitting again, the long cerebrum of time only is capable to do oxygen deficit , make person produce indisposed feeling such as dizzy , lacking in strength.

  Therefore, paying attention to all above, you will be able to feel relieved about the afternoon nap beginning right away!