Do heart patients over-breathe?
In 1995 the British Heart Journal published a study (Clark et al, 1995) done by researchers from the National Heart and Lung Institute in London. The breathing rate of all 88 heart patients at rest ranged from 10 to 18 l/min (or about 2-3 times more than the norm).
In 2000 a study from the Chest magazine a group of American cardiac professionals revealed that patients with chronic heart failure had from 14 to 18 l/min (Johnson et al, 2000).
More recently, Greek doctors from the Onassis Cardiac Surgery Center in Athens recorded ventilation values ranging from 11 to 19 l/min for heart patients from their hospital (Dimopoulou et al, 2001).
These results raise many questions. Are there any heart patients (with primary hypertension, angina pectoris, and other problems) who have normal breathing parameters? Does the normalization of breathing mean no symptoms and no disease for all people? What are the mechanisms of interactions between breathing and heart disease?
How can hyperventilation affect the heart?
Many effects resulting from a CO2 deficiency can influence the cardiovascular system.
* Low blood CO2 values lead to the narrowing of small blood vessels (arteries and arterioles) in the whole body. [Do you remember about this effect (Section 4-A.Vasodilation)?] That causes two problems. First, as a group of Japanese medical professionals found, in conditions of CO2 deficiency, blood flow to the heart muscle decreases (Okazaki et al, 1991). Hence, heart tissue gets less oxygen, glucose and other nutrients. Second, since small blood vessels are the main contributors to the total resistance in relation to blood flow, CO2 deficiency increases resistance to blood flow and makes the work of the heart harder.
* The suppressed Bohr effect, due to low CO2 values in the blood, also reduces oxygenation of the heart muscle. [Do you remember about this effect (Section 4-B. The Bohr effect)?] That increases anaerobic metabolism and produces excessive amounts of lactic acid. Note that lactic acid is often implicated as a source of pain in any tissue. In the case of the heart, a person can suffer from angina or chest pain.
* The excited nerve cells in the heart (the cells that are called pacemakers) interfere with the normal synchronization and harmony in the working of the heart muscle. [Do you remember about this effect (Section 4-C. Stabilization of the nervous system)?] (The valves should open and close in proper time, much like a well-tuned engine.). Desynchronization can make the whole process of blood pumping less efficient or more energy- and oxygen-demanding.
* Abnormal metabolism of fats leads, as Russian medical studies revealed, to increased blood cholesterol level in some people. That condition gradually, over periods of weeks or months, produces cholesterol deposits on the walls of blood vessels in genetically predisposed people. Such deposits can induce primary hypertension. As Russian published studies suggest, the CP has a linear correlation with the blood cholesterol level.
* Chronic hyperventilation affects the normal work of essential fatty acids causing changes in inflammatory responses and the malfunctioning of the immune system.
* Mouth breathing (both at rest and during exercise) is an additional adverse stimulus. It prevents normal absorption of nitric oxide (a hormone and powerful dilator of blood vessels) synthesized in the nasal passages.
The father of cardiorespiratory physiology, Yale University Professor Yandell Henderson (1873-1944), investigated some of these effects about a century ago. Among his numerous physiological studies, he performed experiments with anaesthetized dogs on mechanical ventilation. The results were described in his publication Acapnia and shock. - I. Carbon dioxide as a factor in the regulation of the heart rate. In this article, published in 1908 in the American Journal of Physiology, he wrote, “... we were enabled to regulate the heart to any desired rate from 40 or fewer up to 200 or more beats per minute. The method was very simple. It depended on the manipulation of the hand bellows with which artificial respiration was administered... As the pulmonary ventilation increased or diminished the heart rate was correspondingly accelerated or retarded” (p.127, Henderson, 1908).
* Since heart patients breathe 2-3 times more than the official norm, they usually have more frequent and deeper breathing pattern. That must result in other breathing abnormalities, for example, chest breathing, quick inhalations and exhalations. These irregularities indicate abnormal states of the autonomous nervous and the musculoskeletal systems.
Which parts of the cardiovascular system are going to be most affected?
That depends on genetic predisposition and environmental factors. There are so many factors that can affect the normal work of the cardiovascular system. People are different. Some may get chronic heart failure, others high blood pressure, or stroke, or various abnormalities in the heart muscle.
Do you know that it is possible to get abnormal ECG tracing from a healthy heart just by voluntary heavy breathing? Later, many cardiac professionals, while analyzing such ECGs, can claim pathological changes in the heart. These changes are different in different people. Vice versa, normal breathing naturally eliminates various, already detected, ECG abnormalities.
Modern medicine and physiology has very limited understanding of what is going on with the cardiovascular system when breathing and CO2 values gradually change in one or the opposite direction. There are many questions related to individual variability, mechanisms of developing pathologies, interaction of hereditary and environmental factors.
For the list of the quoted references click here
Information page Previous topic Next topic
© 2008 Artour Rakhimov (If you copy the content of these pages for educational purposes, please, indicate the site address and author's name).
Hosted and Re-designed by:
Trybalink Networking Charity Support
