The nose has a left and a right side; we use both to inhale and exhale. Actually they are different; you would be able to feel the difference.
The right side represents the sun, left side represents the moon. During a headache, try to close your right nose and use your left nose to breathe.  You will be relieved of your headache

 
If you feel tired, just reverse the process. Close your left nose and breathe through your right nose. After a while, you will feel your mind is refreshed.

Right side represents 'hot', so it gets heated up easily, left side represents 'cold'.
Invariably women breathe through  their left nose, so they get "cooled off" faster.
Men breathe with their right nose, so they get worked up.



Have you ever noticed the moment we wake up, the way we breathe? Left or right? ? If you breathe in rapid speedthrough the left nostril you tend to get tired. So, close your left nostril and use your right nostril for breathing, you will get refreshed quickly.
This can be taught to kids, but it is more effective when practiced by adults.
My friend used to suffer from severe headaches and had to frequently visit the doctor..

He took painkillers, did not work. Hence he
 to try out the breathing therapy. He closed his right nose and breathed through his left nose.

In less than a week, his headaches were gone! He continued the exercise for one month.
This alternative natural therapy without medication is something that he has experienced.
So, why not give a try?