Diaphragmatic breathing has the following effects on cardiac function per Dr. Thomas Hanna, author of Somatics: 1) decrease heart rate, 2) decreased cardiac output, 3) reduced peripheral systolic blood pressure [our note: important since hypertension is a major problem in our society], 4) regulation of the cardiovascular system by parasympathetic functions of the autonomic nervous system, 5) regulation of the heartbeat by the ebb and flow of respiratory sinus arrhythmia [ the relationship between the breathing – the lungs – and the heart rate].
Hanna presents the findings from a study that showed that all of the 150+ people in a research study of heart attack patients. Every one of them was a thoracic breather NOT a diaphragmatic breather among them. Swami Rama taught that if you breathe diaphragmatically, with exhale and inhale of the same length, continuously, i.e. no pauses in the breath; you could benefit your heart. Hanna’s observation of this scientific study more than hints at what the yogis knew and have been teaching for as long as they have been presenting the inner knowledge of yoga.