Although breathing is not typically a conscious exercise, you can influence how you breathe, and the amount of air you take into your body. Diaphragmatic breathing -- commonly called belly breathing -- more adequately uses your lung capacity than a shallow "chest" breath. The muscles involved in your breath cycle, like other muscles in your body, can be trained -- learning to use the diaphragmatic breath increases oxygen intake and promotes a sense of calm.
Breathing Muscles
Your body contracts and expands several different muscles to open your chest and allow your lungs to fill with air. The main muscle used for breathing is your diaphragm, located below your lungs. This dome-shaped muscle separates the chest from the abdominal cavity. In between your ribs are a group of muscles called intercostals, and they allow your ribcage to expand and contract. You also use your abdominal muscles to breathe, expanding your stomach to allow room for air and to force an exhalation. Your neck and collarbone area contain muscles that help you breathe in when other muscles involved in breathing are not functioning -- or when lung disease impairs your breathing.
Chest Breathing
Breathing into the upper part of your lungs is called "chest breathing," and it is associated with shorter, more shallow breaths. The upper 10 percent of your lungs transport around 6 mL of oxygen per minute while the lower 10 percent can transport around 40 mL per minute, according to NormalBreathing.com. Chest breathing is often the result of your body's stress response. Chronic stress eventually restricts the connective and muscular tissue in the chest, subsequently decreasing your chest's range-of-motion. If your chest does not expand adequately, the amount of oxygen delivered to your tissues drops, negatively impacting your health.
Diaphragmatic Breathing
Expanding your abdomen when you inhale activates your diaphragm and allows the lower portions of your lungs to take in oxygen. Expanding your belly creates a negative pressure in your chest that not only forces air into your lungs, but also pulls more blood into your chest, increasing the amount that returns to your heart. According to the American Medical Student Association, this action can lead to increased muscle stamina and lymph flow. You may also help prevent lung infections and stimulate your body's relaxation response, promoting calm and lowering your heart rate.
Practicing the Belly Breath
You can improve your oxygen intake simply through conscious practice of the belly breath. Sit or stand with one hand on your chest and the other on your abdomen. When you inhale, focus on pushing the hand on your belly out first, then pulling air up into your chest. Inhale slowly through your nose, and exhale gently, contracting your abdominal muscles to expel all the air. Counting during your inhalations and exhalations can help you keep both even -- as your lung capacity increases, you can increase your count accordingly.
