09 May Variability is the Spice of Life
Every living being is an engine geared to the wheelwork of the universe. Though seemingly affected only by its immediate surrounding, the sphere of external influence extends to infinite distance.
If you want to find the secrets of the universe, think in terms of energy, frequency and vibration.
Variation may be viewed as a fundamental feature of nature and especially so of living organisms. Some features of variation are easily appreciated, for example in the individual diversity of human characteristics or in the change of the seasons. All aspects of human physiology are underpinned by interlocking cycles each with intrinsic frequencies from the beating of our heart, the subject of this monograph, to the timing of daily sleep. With respect to the latter, the human wake/sleep cycle, also known as the circadian cycle, is nearly 24 hours in length and, because it is determined genetically, is quite stable over one’s lifetime. Its activity is kept stable relative to the solar day primarily by exposure of sunlight on the retinae. The timing of many biorhythms such as hormonal secretion, body temperature, gastrointestinal activity, blood pressure, blood sugar metabolism, urine production, mental alertness and EEG activity are related in some way to the circadian cycle. Also connected directly to the circadian cycle are heart and respiratory rates. Our heart beat normally varies, within a narrow range, beat to beat. This variability is driven by the brain through the autonomic nervous system (ANS) and can be shaped by our breathing patterns. Unlike many other physiological activities, control of breathing is something that most people can learn to do. Doing so is a simple and cost-free way of improving health.
What Is Heart Rate Variability
Heart rate variability (HRV) refers to the subtle, but important, variation of the heart rate that occurs during quiet respiration including sleep. Put another way, it is the oscillation in the interval between consecutive heartbeats and, thereby, also oscillations in the instantaneous heart rate which normally have a variance that correlates with the breathing cycle. On the EKG it is frequently called “R-R variability” referring to the distance between the R waves on successive beats (QRS complexes). Respiration consists of two components- inspiration (inhalation) which is normally shorter than expiration (exhalation). Inspiration is an active process compared to expiration in quiet breathing. The diaphragm and accessory breathing muscles contract to suction air into the lungs to allow gas exchange which occurs at microscopic sacks called alveoli. The expanded chest wall then recoils passively to expel the air. Normally the heart beat accelerates slightly with inspiration and decelerates with expiration. This variation in heart rate that occurs with the inspiration/expiration cycle, known as HRV, is a yardstick of cardiovascular and mental health. The greater the variability, the healthier the heart and brain.
As mentioned above, the neurological (nervous system) substrate of HRV is the ANS system which itself has two complementary subsystems, the parasympathetic and sympathetic. The parasympathetic nervous system (PNS) mediates things such as digestion, relaxation, sleep and sexual function while the sympathetic nervous system (SNS), often referred to as the fight or flight system, is responsible for heightening alertness, increasing heart rate, blood pressure and respiratory rate during times of stress. So far as the heart is concerned, parasympathetic input lowers its rate and force of contraction and sympathetic input increases them. When we are relaxed and calm, the heart rate is normally significantly slower than when we are excited, angry or fearful. In fact, other measurably consistent physiological effects of the autonomic nervous system on our bodies when we are under stress such as sweating forms the basis of the polygraph (the lie detector test).
These yin and yang complements of the nervous system mediate things such as sweating, breathing, digestion, muscle tension and cardiovascular health. Imbalance between the SNS and the PNS is a critically important factor in mediating such diseases as asthma, high blood pressure, fibromyalgia, irritable bowel syndrome and, as discussed in more detail below, heart disease. Multiple studies have demonstrated huge benefits to patients with these conditions who practice HRV. It may also help women with pregnancy-related hypertension and preterm labor.
Beyond medical disorders, HRV has been shown to have great benefit in mental illnesses such as anxiety and depression. It is also beneficial in patients with complaints of insomnia. Practicing HRV training is literally a way to put mind over matter.
What Really Causes Heart Attacks?
A specific example of the importance of normal HRV in health and disease can be seen by studying the mechanisms that lead to heart attacks. Multiple studies have demonstrated that a chronic imbalance between the PNS and SNS, as reflected in abnormal HRV, is the major factor triggering heart attacks rather than impairment of blood through the coronary arteries. Specifically, persons at risk for heart attacks have a significant reduction in PNS activity of about one third compared to normal. PNS tone to the heart is mediated by the vagus nerve which also supplies many of our internal organs. This reduction of vagal tone over time leaves the person significantly more susceptible to heart attack because of the relative over abundance of sympathetic (stress) input. Such an imbalance causes a fundamental change in the metabolic status quo, discussed further on, of the myocardium that causes the majority of heart attacks. Thus, there appears to be a healthy dynamic equilibrium between the PNS and SNS which influences the heart rate and many other bodily functions for that matter.
High stress (Type A) individuals, who are typically driven, aggressive and often emotionally reactive, are much more likely to die from heart attack compared to Type B persons. Type A persons have a higher level of stress-related hormones such as cortisol and epinephrine which promote heart disease, among other chronic medical conditions. They are more prone to chronic overwork. Chronic overwork, particularly in demanding jobs, is associated with sleep deprivation as well as long-term psychological distress which likely produce progressive reduction in normal input from the vagus nerve to the heart. This produces a self-reinforcing cycle in such persons that exacerbates the very emotions and behavior that lead to ANS imbalance. In fact, death from work-related stress in Japan is so common that there is a term for it-karoshi. A recent Japanese government study has suggested that up to 20% of its workforce is subject to karoshi which usually causes death from stroke, heart attack and suicide.
A common example of ANS imbalance due to loss of PNS input in medical practice occurs in diabetic patients with autonomic neuropathy. Chronically elevated blood sugar is known to produce serious damage to certain organs/systems including the peripheral nervous system part of which is the ANS. These patients often have little or no variability in the heart rate from beat to beat because the disease has left them with an overly dominant SNS because the normal input or tone from the parasympathetic system has been reduced by injury to the vagus nerve. Diabetics with autonomic neuropathy have a particularly high risk of sudden death from heart attacks. This lack of HRV in these patients is easily seen on a standard EKG.
Chronic loss of normal vagal tone is also reflected in the loss of the normal circadian variance of HRV. The normal increase in restorative PNS activity that occurs during sleep is absent implicating hypothalamic dysfunction in these persons. [The hypothalamus contains the pacemaker of the circadian rhythm and regulates sleep, feeding, blood pressure and influences locomotion.] The fact that most heart attacks occur during sleep is likely related to the normally occurring periodic surges in SNS activity during REM sleep which trigger a metabolic cascade leading to acute cardiac dysfunction. Conversely, there is no evidence of chronic increased basal sympathetic tone based on HRV analyses in persons with reduced PNS tone. In general, women have higher vagal tone than do men.
Other factors besides chronic stress and diabetes which reduce normal PNS tone include high blood pressure and cigarette-smoking. The standard drugs used to treat heart disease e.g. aspirin, nitrates and statins increase vagal tone to a point. However, eventually they lead to a rebound decrease in PNS activity.
What Happens During a Heart Attack?
What follows regarding the events during a heart attack assumes the patient already has an abnormally reduced vagal tone i.e. decreased baseline PNS activity. Autopsy studies have shown that blood clots are an infrequent cause of heart attack but are often a consequence of heart attack. Furthermore, most doctors would be stunned to learn that studies of acute heart attack have shown no change in oxygen levels within the heart muscle (myocardium). This is contrary to the mainstream view that lack of blood to the myocardium from occluded coronary arteries is the main culprit of heart attacks.
Instead, what happens typically is an acute physical or emotional stress increases instantaneous SNS activity which stimulates the release of large amounts of adrenaline (epinephrine). In the minutes leading up to a heart attack there is also a further reduction of the already abnormally low protective vagal tone of the PNS.
The excess epinephrine induces the myocardium to switch from its preferred energy sources of fatty acids and ketones to glucose (sugar). The metabolism of glucose in this setting occurs aerobically i.e. with oxygen, leading to the production of excess lactic acid lowering the pH of the cells. The resultant acidity causes the cellular proteins, including the contractile proteins, myosin and actin, of the heart cells to lose their three-dimensional shape (denaturing) necessary to function properly. It also inhibits influx of calcium ions into the heart cells further blocking cellular contraction.
Additionally, the low pH results in failure of energy production allowing water to flow unrestricted into the cells which begin to swell. The nonfunctioning cells then begin the process of programmed cell death. The non-contractile segment of the heart causes impaired blood flow in the coronary arteries which supply it as a secondary event, an epiphenomenon that is often associated with clots after the damage has been done. This lack of blood flow accelerates the production of lactic acid worsening the cellular acidity. As mentioned previously, this cascade is possible only in persons with abnormally reduced baseline vagal tone i.e. reduced PNS activity.
How to Avoid a Heart Attack
The milieu for engendering heart disease may be equated with the trappings of industrialized civilization which have resulted in an overworked, sleep-deprived, malnourished society. The effects of industrialization have been present for centuries in Europe. For example, the infectious scourges such as small pox, tuberculosis and sexually transmitted diseases of the Old World were unknown in this hemisphere until after the first Spanish explorers arrived. Why was that the case? Diaries of Spanish monks remarked on the evident abundant health and happiness of the indigenous people of the Americas and of the cleanliness of the cities compared to those of Europe.
An increasingly inordinate amount of time in modern society is spent in (often stressful) pursuit of material gratification of one sort or another. The quest for ‘stuff’ in lieu of meaning in our lives frequently leads to over work which manifests in overtime or holding more than one job at a time. I was shocked to learn that a peasant in medieval England was able to provide for his family by working only about 14 weeks a year. Contrast that with today’s work schedule in which two weeks’ vacation annually is standard. Promoting a healthy heart and over all good health means turning away from the innumerable materialist gratifications of modern life. For most this will mean a radical change in diet and a re-thinking one’s entire philosophy regarding the pursuit of happiness.
A healthy diet avoids processed i.e. manufactured, food which is usually high in sugars and low in nutrition. Processed food is a prescription for weight gain which itself is the prime mover of most chronic illnesses such as cardiovascular disease, diabetes obstructive sleep apnea and even cancer. Whole plant-based diets are associated with better health.
Finally, people who are happy are less prone to heart disease. They report greater satisfaction in their vocations and relationships. They are secure in their own lives and are more likely to trust others. They typically have a profound sense of meaning in their lives and the lives of other people allowing them to find pleasure and even joy in the pedestrian miracles of quotidian life.
How is HRV done?
Practicing HRV training is easy. It restores the normal balance between the PNS and the SNS through calming the mind. The overall idea is to slow one’s respiratory rate to about five or six breaths per minute. As I mentioned earlier, exhalation is normally longer than inhalation in quiet breathing. I tell my patients to count by 1000s as they begin inspiration. For most people they will get to about one thousand three or one thousand four by the time inspiration is finished. At the initiation of expiration they begin counting by 1000s again but should go longer than inspiration. For example, if you get to one thousand three on inspiration, you should go to at least one thousand four or five with expiration. As you get more practiced the expiratory phase will last longer and long to about one thousand ten or so. There is a brief pause between inspiration and expiration.
An abundance of clinical research has confirmed the benefit of HRV training to treat high blood pressure, asthma, insomnia, improve post heart attack rehab and reduce anxiety. One can expect to see results in a few weeks. I suggest doing it nightly at the beginning for at least two to three minutes initially. Work your way up to about ten minutes at a stretch at which point doing less frequently will suffice. It can be done anywhere or any time you do not have to speak. I do it before lights out for at least 10 minutes while listening to Solfeggio frequencies.
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