Weather or not you like the Vedantic concept of Prana, (breath or life-force), you must understand that breath is the most necessary requirement to sustain human life. We can go weeks without food and days without water, but only for minutes without breath!
The average person breathes with the top part of the chest through the front of the nose, using less than half of the available lung capacity.
This is typical of my friend Joe who was having trouble with an asthmatic condition. The various medications the Doctors had given him were loaded with side effects that seemed worse than the original symptoms. After six fifteen minute sessions over a two week period he learned to breathe through the back of his nose into his lower diaphragm.
With the use of extra lung capacity and a bit of healing Light, he eliminated his chronic cough as well as the medicines he was on.
How about you? Are you using your nature given lung capacity to it's fullest? Try a simple test: place your hand flat against your waist, with half above and half below the belt line on your "back." Now take a deep breath. If you don't feel the lower back muscles moving straight back as you inhale, you are missing the most important part of lung area.
Practice making the air produce a funny sound in the back of your nose as your back muscles pull the life giving air deep into your body.
When I take a deep breath before chanting, it sounds like someone blowing up a balloon. So you will know when you are breathing properly by the sound and the extra life-force it gives you.
Good Luck, Good Magic and Good Breath,