Heart Rate Variability Assessment
The Brief Explanation
Heart Rate Variability Assessment is the specialized use of an electrocardiogram to objectively measure an individual’s level of health and physical function. Overwhelming scientific research in mainstream medicine has proven that sophisticated mathematical analysis reveals the connection between the variability of the heart beat, the state of the autonomic nervous system (which controls all our internal organs and involuntary functions), and overall health.
The mathematical algorithms used in the specific system employed by Dr. Weeks were developed and tested for over seventeen years in studies involving more than fifteen thousand patients, and have been certified by the Cardiology Division of the Columbia University College of Physicians and Surgeons.
What is it like to have a Heart Rate Variability Assessment done? A single electrode, sufficient for this type of analysis, is strapped to your bare chest over your heart, and your shirt is worn over that. A lead attached to your clothing sends the heart beat signal to the computer. First, you will lie comfortably on your back with your eyes closed for 3-4 minutes, then you will be told to stand up briskly. After standing for 3-4 minutes the electrocardiogram will be complete. The computer will instantly perform the mathematical analysis.
You should consume no stimulants or unnecessary medication the day of the test, and be well hydrated.
Why is variability of the heart rate so important? To understand that, we first have to recognize that our health depends on how well our body can constantly adjust all of its functions to the myriad of stimuli and demands that are continually changing. Temperature, light, noise, time of day, blood sugar, an endless list of stress and change of all kinds require our body to regulate itself around a point of balance. The better it can do this the healthier we are. The more our bodyÃ¾s ability to adapt to this constant change declines, the sicker we become. In the case of the heart, it must constantly regulate its output of blood to demands for blood flow that change every instant. Studies have demonstrated that decrease in heart rate variability emerges as the single most common risk factor for all kinds of chronic diseases such as diabetes, chronic fatigue, heart failure, neurologic disorders, and many others.
The results are easiest to understand by looking at two of the graphs. One plots the function of the Parasympathetic Nervous System (PNS) versus the Sympathetic Nervous System (SNS). Simply stated, the PNS nurtures, rebuilds, and rejuvenates us. The SNS always dominates in times of stress or crisis, and generates our “fight or flight” response. Eventually, our stress response can deplete energy reserves so they are not available for the parasympathetic nervous system. In poor health and with very little reserves, both systems become depleted as the parasympathetic is “eaten up” and can no longer rebuild health, and the sympathetic also starts to fail as regulation of internal functions shuts down further. Results in the first graph can also indicate whether emotional stress is taking a physiological toll.
The second graph plots fatigue versus reserve capacity. Reserve or vital capacity is extremely important. It indicates the degree of exhaustion and the ability to recover from fatigue or adapt to any level of prolonged stress. It is a truly objective indication of our functional condition, how “healthy” we really are. These two graphs considered together determine overall physiological performance.
In summary, overwhelming scientific research in mainstream medicine proves the connection between Heart Rate Variability, the autonomic nervous system, and health. A decrease in HRV emerges as the single most common risk factor for many different kinds of chronic disease. The Heart Rate Variability Assessment measures stress on the body, how the body is coping, and to what degree it has had a deleterious effect. This is extremely helpful in determining what type of therapy is needed or able to be tolerated. It can show whether treatment has really helped or just suppressed symptoms, and whether there is a significant emotional component. It can help determine whether detoxification, drainage or chelation therapies should be applied or a strengthening orthomolecular approach must be used first. It can show whether bioenergetic therapies like homeopathy or acupuncture are likely to elicit the desired change, or whether they are unlikely to produce a beneficial response. And it can indicate how long a recovery period may be expected.
The Old Reliable Treadmill May Be Better Than High Technology: An Example of Heart Rate Variability
An often-ignored measurement taken during routine treadmill “stress tests” can predict a heart patient’s risk of early death even better than many expensive, high-tech approaches. Cleveland Clinic researchers found that the heart’s recovery rate – how much the heartbeat slows after someone exercises to exhaustion and stops – can help doctors spot those patients needing aggressive treatment.
Exercise stress tests, used since the 1960s, involve having a patient walk on a treadmill while his or her heart rate, blood pressure and the heart’s electrical currents are monitored. The test costs about $600. Since the mid-1980s and early ’90s, however, doctors have used more sophisticated tests also involving a treadmill: stress echocardiograms, or ultrasound images of the heart pumping, costing around $1,500; a nuclear imaging technique called thallium scintigraphy, costing about $2,400; and a nuclear “video” showing sections of the heart that are not pumping properly.
Normally, when someone exercises to exhaustion and then stops, the heart rate drops 15 to 25 beats per minute. The researchers found that for patients whose heart rate fell less than 12 beats one minute after exercising, the risk of dying within six years was four times greater than for those above the cutoff. This was the number that best discriminated between people who were going to live and people who were going to die. Normally doctors focus on other results from a treadmill test: how the patient feels, his endurance, how much his heart rate increases, and changes in the heart’s electrical currents. The researchers found 19 percent of patients whose heart slowed less than 12 beats per minute in the first minute after exercise were dead within six years. Of those with a normal heart-rate recovery, only 5 percent died in that time. The recovery rate as measured by a treadmill test was twice as good as thallium scintigraphy at predicting death.
New England Journal of Medicine October 28, 1999;341:1351-7
COMMENT: This is an example of studies related to heart rate variability analysis. The increase in heart rate that accompanies exercise is due in part to a reduction in the parasympathetic nervous system tone. Recovery of the heart rate immediately after exercise is also a function of the parasympathetic nervous system. A generalized decrease in parasympathetic activity is known to be a risk factor for death from all causes, and an indication of autonomic nervous system dysregulation in a global sense. A delayed decrease in the heart rate during the first minute after exercise stress, which may be a reflection of decreased parasympathetic activity, is a powerful predictor of one’s risk of dying from heart disease and many other causes. But we now have in the HEART RATE VARIABILITY ANALYSIS an incredibly simple tool that measures overall vital capacity (cardiac reserve) to evaluate one’s risk of dying from heart disease and other causes, and also analyzes parasympathetic versus sympathetic nervous system function overall for global regulatory capacity. These are very valuable functional indicators for health analysis, determining what kind of therapy is most suitable, and objectively evaluating response to treatment. One does not even need an exercise stress beyond the orthostatic challenge (abrupt shift in posture from lying to standing) to perform this test.