This flat muscle separates the chest from the abdomen and is your breathing muscle.
Breathing with your diaphragm triggers a deep breathing pattern filling your lungs with air more efficiently. Many people do tight, shallow chest breathing and not engaging your diaphragm effectively.
To know what type of breathing you do, put one hand on your chest and one hand on your stomach. Then inhale and see what hand moves the most. If the hand on your chest moves the most you are doing shallow breathing. If your hand on abdomen moves most, then you are engaging your diaphragm to do deep breathing.
[…] your diaphragm for breathing and not your chest will cause your lungs to fully fill up with air making breathing more efficient. […]