The first thing is to keep a check onto how, you actually breathe. Is it just the chest which is at work or you go deeper into the lower belly.
The diaphragm is an important gateway of the breath. In a healthy breath your diaphragm expands downward when you inhale. But you must make sure your body and your emotional state is relaxed. Your diaphragm is tightened when you are upset or filled with worries.
You must sit straight with your spine lined with the place you are resting your back to!
Then let each breath deepen into your belly and allow it to roll up from the inside the spine. This motion will create lift as well as traction with each inhale. For the exhale, allow your body to deflate and bend a bit forward as you empty yourself. Replicate this movement of wave-like breathing for some time.
How you must expand the breath capacity with this method?
This is the second stage, where you will be expanding your breath capacity. In this step you got to concentrate on your inhalation process, by deepening it within the pelvis area and till ribs. It releases tensions and breaks through the emotional blockade in the body. As you all know Pranayama is the core of yoga, you will be surprised to know it is the basic of all forms of exercises, physical activities or deep breathing techniques. It regenerates and liberates the body internally and allows maximum strength and focus for all sorts of physical and emotional strenuous activities.
Try this…
Place your right hand on the lower belly and left one on the upper chest. Start filling up the lower belly then your chest alternatively. This is exaggerated breathing; it stretches out the body from the inside out.