When breathing becomes easier, the heart does not have to work as hard. When you try to breathe too quickly, as in a race or when you are frightened, you excite the nervous system and this excitation locks up the expansion potential of the muscles holding the rib cage together. This reduces the ability for the chest to easily expand and the lungs to take in extra oxygen easily. There is a naturally calming, breathing reflex that becomes eroded by forcing the breath too much or too often. Even world class athletes and woodwind players can develop asthma and other forms of restricted breathing.
Difficulty breathing makes day to day living harder.
The stress of unbalanced breathing can break down the body's resistance to disease by using up valuable oxygen needed for healthy metabolism as well as cause the vital organ system to overwork and become vulnerable to disease. There are many hidden degrees of restricted breathing or what I call latent shortness of breath. Asthma and emphysema are easy to spot. But asthma and emphysema don't just suddenly enter your body. They often take years to develop.