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The diaphragm, a dome-shaped muscle at the base of the lungs, plays an important role in breathing — though you may not be aware of it. When you inhale, your diaphragm contracts (tightens) and moves downward. This creates more space in your chest cavity, allowing the lungs to expand. When you exhale, the opposite happens — your diaphragm relaxes and moves upward in the chest cavity.

All of us are born with the knowledge of how to fully engage the diaphragm to take deep, refreshing breaths. As we get older, however, we get out of the habit. Everything from the stresses of everyday life to the practice of "sucking in" the stomach for a trimmer waistline encourages us to gradually shift to shallower, less satisfying "chest breathing."
But it's especially important for people with chronic obstructive pulmonary disease (COPD). In COPD, air can become trapped in the lungs, which keeps the diaphragm pressed down. This causes it to weaken and work less efficiently. Diaphragmatic breathing can help people with COPD strengthen the diaphragm, which in turn helps them use less effort and energy to breathe.Relearning how to breathe from the diaphragm is beneficial for everyone. Diaphragmatic breathing (also called "abdominal breathing" or "belly breathing") encourages full oxygen exchange — that is, the beneficial trade of incoming oxygen for outgoing carbon dioxide. Not surprisingly, this type of breathing slows the heartbeat and can lower or stabilize blood pressure.

Here's how to do it:

• Lie on your back on a flat surface (or in bed) with your knees bent. You can use a pillow under your head and your knees for support, if that's more comfortable.
• Place one hand on your upper chest and the other on your belly, just below your rib cage.
• Breathe in slowly through your nose, letting the air in deeply, towards your lower belly. The hand on your chest should remain still, while the one on your belly should rise.
• Tighten your abdominal muscles and let them fall inward as you exhale through pursed lips. The hand on your belly should move down to its original position.

You can also practice this sitting in a chair, with your knees bent and your shoulders, head, and neck relaxed. Practice for five to 10 minutes, several times a day if possible.