Have you ever seen how, when an infant breathes, its whole body expands and contracts? The reason this happens is because infants breathe with "diaphragmatic belly breaths"; the most efficient way to breathe.
As infants grow up, for reasons possibly having to do with emotional traumas, they often shift from belly breathing to chest breathing. This is why most adults who have not been trained in breathing, breath by expanding and contracting their chest rather than their belly.
Before going any further, let's briefly look at how breathing happens. The diaphragm, the principal muscle of breathing, attaches all around the peripherty of inside of the human torso, dividing the torso into two cavities, the upper, thoractic cavity, containing the heart and lungs, and the lower, abdominal cavity, containing the stomach, liver, gall bladder, kidney, intestines and other organs. When the diaphragm is relaxed, it has a sort of double-dome shape with the top of the dome lying just below the lungs. When the diaphragm contracts, the domes flatten, stretching the thoractic cavity downward and stretching the lungs down, creating space inside of them, and this causes inspiration. When the diaphragm relaxes, the natural elasticity of the structures surrounding the lungs causes the lungs to contract back into their initial shape, forcing the air out in exhalation.
Whether we breath by expanding the belly or the chest depends upon which muscles other than the diaphragm are used when breathing.
Belly breathing is not only the way we are born breathing, but it is also the most efficient. Belly breaths better use the portion of the lungs where there is greatest gas exchange, and also allow the breather to have a smooth and long breath. This is why singers re-learn to breathe this way. The practioners of yoga discovered, through their experiements with their bodies, that belly breathing allows one to control his/her breath better, and also that doing so has a natural relaxing effect. This is why those who are trying to learn to relax are taught to belly breath.
Chest breathing, on the other hand, is not effecient and associates with agitation. When one chest breathes, the breath is not brought into the area of greatest gas exchange. Also, there is a natural association between rapid chest breathing and excitement. So, if one wants to be calm, the better choice is belly breathing.
So how to do belly breathing?
Here are two simple exercises from yoga that will help one to re-establish the habit of belly breathing . The first is done lying on the belly in the crocodile pose (makarasana in Sanskrit). The second is done lying on the back in the corpse pose (shavasana in Sanskrit).
1. Diaphragmatic Belly Breathing in Crocodile pose:
Place a clean yoga mat or blanket on the floor, and lay down on your belly. Cross your arms with one hand on each elbow, elbows on the floor about seven inches forward of the shoulders, and lay your head on your forearms. The arms should be far enough forward of the shoulders so that your chest is slightly lifted off the floor, but not so far lifted that you can't comfortably place your head on the forearms.
The legs are either spread apart in a "V" shape with the heals falling toward one another, or, if this isn't comfortable on the lower back, the legs may be together with the heals falling away from one another.
Breathe deeply and slowly and notice how as you inhale the belly presses against the floor, and how this pressure is diminished when you exhale. If this is happening, you are belly breathing. The crossed arms lock up the chest to some extent to encourage belly breathing. Deepen and lengthen the breath if you can, and let it flow smoothly without jerks or stops. Seek to breathe so that the inhalation and exhalation are equal in length.
Continue breathing like this for up to ten minutes, keeping your awareness on the smooth flow of the breath and the sensations of the belly pressing against the floor on inhalation and the pressure diminishing on exhalation.
If your mind wanders into thoughts, dreams, etc., bring it back to awareness of the sensations of breathing.
When finished, take a few moments to notice the effects of the practice, and then, with care, you may get up and carry on with your activities.
This exercise will help regain the habit of belly breathing if you do it daily for a month. As you practice, you'll find yourself able to belly breath at will. As you master breathing this way, you'll be able to belly breathe sitting up and even walking. Anytime you do, you'll likely feel more relaxed and energized.
2. Diaphragmatic Belly Breathing in Corpse pose:
Lie on your back on a clean mat on the floor, or, if you are wanting to relax to go to sleep, you may lie on your bed. Place the little finger of your left hand in your navel and spread the rest of the fingers of the left hand toward your chest on the upper abdomen. Place the right hand in the center of your chest, between the breasts.
Breathe deeply and smoothly, and notice whether your belly, chest or both move as you breathe, using your hands as guages. The goal in this practice is to breathe as if into and out of your belly, so your left hand on the belly rises on inhale and falls on exhale. The right hand, on your chest, should remain relatively still. Your habit might be to breathe in a different way, such as with your chest rather than belly. If so, it might take some experimenting on your part to breathe this way. Take time experimenting and be gentle with yourself, and you'll learn to breathe so your belly rises on inhale and falls on exhale. Seek to breathe smoothly, without any pauses or stops in the breath, with inhalation and exhalation equal in length. Practice breathing this way for five or ten minutes.
When finished, take a few moments to notice the effects of the practice, and then, with care, get up and carry on with your day.
These exercises will help regain the habit of belly breathing if you do one of them daily for a month. After some practice, you'll find yourself able to belly breath at will. As you master breathing this way, you'll be able to belly breathe sitting up and even walking. Anytime you do, you'll likely feel more relaxed and energized.
Thanks to Dr. Paul Emerson for his invaluable feedback on this article.
The instructions for corpse pose breathing were adapted from the book Freedom From Stress, by Dr. Phil Neurnberger.
A source for this article and an excellent reference book on the structures and processes of breathing is Yoga Anatomy, by Leslie Kaminoff