Contrary to the common assumption, a healthy heart doesn't beat regularly like a metronome. The heart's moment by moment beating rate is naturally influenced by many physiological factors and varies constantly. The most obvious of these factors is how your heart responds to the demands of physical activity. At rest, for example, your heart might beat about 60 times per minute. When you're running or swimming, it might accelerate to well over 90 beats a minute. In fact, the range defined by your minimum to maximum heart rate capacity is a key factor defining your level of health. As a person's physical condition deteriorates, this range can actually become narrowed to the point of limiting their ability to adapt to the stresses of daily life. From that point on, any unexpected stressful condition could push the individual to the limit of their adaptability and put them at risk for cardiovascular accidents and possibly death. (source: Combatalade, 2010 )
The idea of exercising the cardiovascular system to maintain as wide as possible a range of heart rate adaptability is not new. Medical practitioners have prescribed physical exercise and stress management techniques, such as meditation or yoga, for generations. In recent years, a novel biofeedback method has gained serious recognition from practitioners of many health care professions. A set of standard signal processing and analysis methods, proposed in 1996, has been widely accepted by practitioners and manufacturers of equipment. A number of heart rate variability (HRV) biofeedback protocols have been developed and tested for various clinical conditions. The research shows sufficient evidence of success that it places HRV biofeedback ahead of many other self-regulation methods in terms of acceptance by mainstream medicine.
Vagal nerve tone is implicated in many neuro-cardiac problems. The amount of change in heart rate with change in breathing is an index of vagal tone. It is simple to evaluate relationships between heart rate variability and respiration using biofeedback equipment.
Biofeedback as an Integral Component of Cardiac Rehabilitation
Patients with coronary heart disease (CHD) who experience depressed mood or psychological stress exhibit decreased vagal control of heart rate (HR), as assessed by spectral analysis of HR variability (HRV). Myocardial infarction and sudden cardiac death are independently associated with depression and stress, as well as impaired vagal HR control. Many high quality studies in the last five years show that HRV and breathing biofeedback, coupled with behavioral neurocardiac intervention to reduce stress or depression, can augment cardiovagal modulation in CHD patients.
Gevirtz and his team (e.g., DeGuire et al 1996) as well as many others have shown that there is a solid relationship between anxiety and non-cardiac related chest pain. They have also shown that abnormal patterns of respiration well known to lead to feelings of anxiety due to changes in concentration of carbon dioxide, also result in non-cardiac chest pain. The literature indicates that between 51 and 90% of non-cardiac related chest pain is associated with hyperventilation. Retraining breathing patterns results in long term (at least three years) control of stress related cardiac pain symptoms and hyperventilation related symptoms such as anxiety. See Gevirtz's placebo controlled, long term follow-up studies (e.g. DeGuire et al 1996) for details of their findings. It is emphasized that correction of these breathing patterns relieves the chest pain or eliminates it all together without further intervention to correct an anxiety disorder. Thus, it is the sequeli of incorrect breathing which create both anxiety and chest pain for many patients - not an underlying anxiety disorder which results in incorrect breathing.The newest approach involves using biofeedback to maximize heart rate variability in relation to respiration in order to treat cardiac pain. The idea is that variability increases and decreases as people breath in and out. Patients are trained to maximize variability by watching the display. The technique is currently called "Resonant Frequency Training" (RFT) and was previously called respiratory sinus arrhythmia biofeedback (RSA). The literature supporting the technique's efficacy is solid (e.g. Gevirtz 1999, Gevirtz 2002, Lehrer et al 2000). * Much of the information provided here is from Carolyn Yucha and Christopher Gilbert's 2004 book "Evidence Based Practice in Biofeedback & Neurofeedback" AAPB, Wheat Ridge, CO.
Why biofeedback treats noncardiac chest pain:
People's hearts do not beat at a steady rate. Rather, they change with exercise, emotions, and breathing. There is a well known relationship between chest pain caused by anxiety or incorrect breathing patterns and heart rate variability. If variability is too low in relation to breathing, non-cardiac chest pain may be observed. Training people to increase the variability of their heart rates in relation to their breathing results in decreased symptoms of non-cardiac related chest pain.
Numerous high quality studies have demonstrated that people having high blood pressure - especially if it is stress related - can benefit extensively from biofeedback as long as they learn and practice the skills needed to control their blood pressures. Many hypertensives no longer need any medications after successful biofeedback training.
Why biofeedback treats stress related hypertension:
There are many reasons why a person may have high blood pressure. One of the most common is abnormal increases in blood pressure due to stress. Increased blood pressure is one of many normal responses to stress. Sometimes blood pressure goes up so much that a highly reactive person's ears turn redder, and may even tingle and / or ring. This is a normal response to stress. For some people, these increases don't return to normal levels for a long time. The time to return to normal may take longer and longer until blood pressure never returns to normal. The person has now developed high blood pressure. Biofeedback based treatments help people recognize and control their response to stress and also help them recognize when they are successfully controlling their blood pressures. Thus, biofeedback can directly and indirectly help people learn to control blood pressure.