typical adult engages as little as 10 percent of the range of the diaphragm when breathing, which overburdens the heart, elevates blood pressure, and causes a rash of circulatory problems. Extending those breaths to 50 to 70 percent of the diaphragm’s capacity will ease cardiovascular stress and allow the body to work more efficiently. For this reason, the diaphragm is sometimes referred to as “the second heart,” because it not only beats to its own rhythm but also affects the rate and strength of the heartbeat.
