Breathing Matters > Heart

Breathing affects the heart in a number of other ways. The heart rate rises during inhalation, and decreases during exhalation. This normal heart rhythm fluctuation, called respiratory sinus arrhythmia (RSA), contributes to cardiac efficiency. Men, with little evidence of this normal fluctuation, are more likely to die suddenly. When one breathes rapidly, as is commonly seen in anxiety and depression, normal respiratory sinus arrhythmia is lost. Anxious people are at increased risk of sudden death while depressed people also have an increased risk of heart disease.

Hyperventilation causes a respiratory alkalosis. Haemoglobin in alkalotic blood supplies less oxygen to the heart; it hangs onto the oxygen more tightly. In physiological terms, this is called the Bohr effect. The heart, in a hyperventilating person in sympathetic overdrive, has to beat harder against an increased resistance. If RSA is not present, some cardiac efficiency is lost. A reduced oxygen from the red blood cell haemoglobin leads to a reduced oxygen supply to the heart muscle. Changes in the body pH(alkalosis) could lead to disturbances in the electrical activity of the heart. Changes in the electrical activity (ECG) of the heart are seen in hyperventilating patients. People, who breathe poorly, simply place an increased strain on their hearts.

Breathing slowly, focusing on a slow exhalation phase, improves parasympathetic tone, thus improving RSA. Breathing reeducation significantly reduces the risk of further heart attacks. Breathing reeducation improves breathlessness, exercise tolerance and blood oxygen levels in people with heart failure. Attention to breathing patterns, not only helps those patients who are hyperventilating, but if you have heart disease also benefits both your heart and your blood pressure.