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Heart Rate Variability: Powerful Tools for Reducing Cardiovascular Risk
By Lee Lipsenthal, MD
Finding Balance in a Medical Life
Past President:
American Board of Holistic Medicine
Heart Rate Variability, the beat to beat change in heart rate, is an accurate indicator of autonomic nervous system activity that can provide important insights into a patient’s risk of cardiovascular disease. More importantly, it can play a central role in teaching patients how to reduce their own risk by showing them how their emotional states affect their heart health.
Heart Rate Variability has been used in medicine since the 1960s, initially in obstetrics. HRV is what is measured in ‘fetal monitoring,’ and indicates the well being of the fetus’ autonomic system. It has also been heavily researched in cardiovascular disease, especially in relationship to arrhythmias. Rapid HRV changes can trigger atrial arrhythmias. Treatments affecting HRV may be useful in treating arrhythmias.
In essence, HRV provides a picture of the interplay between the sympathetic and parasympathetic branches. As such, it reflects the ways in which emotional states affect core physiology including, but not limited to, cardiac function.
As sympathetic tone increases, the heart’s beats (R-R intervals on the EKG) get closer together. As parasympathetic tone increases, they widen out. The ebb and flow of autonomic tone create patterns of heart rate acceleration and deceleration; thus HRV provides a picture of emotional and physiological states.
Heart Rate Variability: Two Basic Patterns
here are two basic patterns of Heart Rate Variability (see diagram). The incoherent HRV pattern (Top) is characterized by a low peak-tonadir difference in the waveform of the heartbeat, and it is typical of states of high sympathetic tone. Chronic sympathetic overactivity, as seen in states of depression, anger, anxiety and hostility, trigger increases in parasympathetic tone, reflecting the autonomic system’s attempt to achieve homeostasis. In a simple but reasonable analogy, it is like running your car with your foot on the gas and brake at the same time: the conflicting signals produce discordant function, which is reflected in the jagged and incoherentform of the HRV pattern.
The more coherent HRV pattern (Bottom) associated with positive emotional states represents a balanced, cohesive ebb and flow of sympathetic and parasympathetic tone. This occurs when both tonalities are at modest to low output, and it is characteristic of lowstress, high-satisfaction emotional states.
Low HRV is associated with high sympathetic tone, and the detrimental cardiac effects of chronically elevated sympathetic tone are very well documented. They include increased arrhythmias, vasoreactivity, hypercoagulabilty, and thrombosis (Sudhair V, et al. Am J Cardiol. 1994; 73: 653– 657). Low HRV patterning is also associated with higher risk of sudden death and MI in patients with CAD (Khaykin Y, et al. Can J Psychiatry. 1998; 43:183–186. Enhancing Recovery in Coronary Heart Disease Patients (ENRICHD) Study Group. Am Heart J. 2000; 139: 1–9. Bernardi, et al. BMJ 2001; 323:1446–1449 Blumenthal JA, et al. Am J Cardiol. 2002 Jan15; 89(2):164–8. Carney RM, et al. Psychosom Med. 2000; 62:639–647)
Incoherent Heart Rate Variability is also found in people with CAD who are depressed. In Carney’s post-MI study, those who were depressed had consistent incoherent Heart Rate Variability patterns compared to those who were not depressed. HRV was equally incoherent in those who had major depression, minor depression, or dysthymia, compared to those without depressive symptoms.
Emotional States andHeart Rate Variability Patterns
The Institute of HeartMath, an institute dedicated to the study of the physiology of emotions, was founded in 1991 by a group of educators, engineers and researches. HeartMath has published many studies evaluating the relationship of emotions and HRV (McCraty, R, et al. Am J Cardiol. 1995; 76:1089). In one study, power spectral density (PSD) analysis of HRV was used to compare autonomic activation and sympathovagal balance in subjects during a 5-minute baseline period, followed by a 5-minute period of self-induced anger, and then a 5-minute period of appreciation. These experiments used HeartMath’s Freeze Frame® technique, a biofeedback method based on HRV.
The researchers found that both anger and appreciation caused an overall increase in autonomic activation, as demonstrated by an increase in power in all frequencies of the HRV power spectrum, as well as an increase in mean heart rate. However, the two emotional states produced very different effects in terms of sympathovagal balance.
Anger produced a sympathetically dominated power spectrum, whereas appreciation produced a shift toward increased parasympathetic activity (Tiller, W., McCraty, R., & Atkinson, M. Altern Ther Health Med. 1996: 2(1):52). These shifts were correlated with shifts in HRV to ‘healthier’ patterns correlating with lower cardiac risk. These and other findings from the HeartMath researchers strongly suggest that shifting to and maintaining a sincere, positive emotional state may shift physiology towards overall better health. This may explain why optimists have significantly lower mortality than those who are generally pessimistic (Kubzansky LD, et al. Psychosom Med. 2001; 63:910– 916).
Emotional Shifting andHealth Improvement
Emotional shifting refers to techniques that help an individual switch their emotional state consciously. These can be quick and easy, such as changing one’s focus from an emotionally agitating situation to an emotionally calming or joyful one, or they can be longer, deeper and more involved, such as routine practice of a lovingkindness meditation.
Emotional shifting techniques have been studied in workplace settings, including hospitals and clinics, schools, and clinical environments. A host of data shows these techniques can reduce stress, depression, and negative emotion, while enhancing positive emotion, communication, and job satisfaction.
The techniques have significant physiological benefits, including enhanced autonomic nervous system balance as measured by HRV, reduced cortisol levels and increased DHEA (McCraty R., et al. Integrative Physiol Behav Sci. 1998; 33(2): 151.), improved immunity (Rein G, Atkinson M, McCraty R. J Adv Med. 1995; 8(2):87.), reduced blood pressure (McCraty R. J Altern Compl Ther. 2003; 9(3):355–69.), and improved exercise capacity in people with congestive heart failure (Luskin F, et al. Prev Cardiol. 2002; 5(4): 168–172.).
Emotional shifting techniques have also been shown to decrease hemoglobin A1c in a diabetic population (McCraty et al., 1999). This is likely due to decreases in catecholamines and cortisol, both of which enhance gluconeogenesis and glycogenolysis.
When shifting from a thought that is angry, hostile, or depressed to a mood state of appreciation in tune with one’s values, there is first a decreased release of catecholamines. Thisthen alters output from thevagus nerve to the body. Thisshift in vagal tone triggers ashift in Heart Rate Variability, which then sendsinformation to the cortex, viathe midbrain, to help facilitatecortical function. In simplerterms, when you relax and gethappy, you get smarter.
Heart Rate Variability and EmotionalShifting in the Workplace
In a study of employees of astate agency in California, theHeartMath emotional shiftingtechniques were taught to 54employees over the course ofsix weeks. This period happenedto coincide with budgetcuts and layoffs in this organization,a stressful time formany employees.
Participants applied Heart-Math emotional shifting toolsto the issues, challenges, and opportunitiesinherent in fundamentalorganizational change.They were taught Freeze Frame®,a more advanced problem solvingtechnique using the QuickCoherence® concepts. Theyalso learned the Heart Lock-In®, a technique similar to anappreciation meditation donefor 20 minutes daily. A psychologicalsurvey measuring stress,negative emotions and organizationaleffectiveness wasadministered pre- and posttraining.Participants were comparedwith a group of 64employees who had not undergonethe HeartMath training.
Seven weeks from the initialassessment, the HeartMathgroup showed significant reductionsin stress and negativeemotion, and significant increasesin measures of positiveemotion and organizational effectivenesscompared with thecontrols. Key findings includeddecreased anger (20%), distress(21%) depression (26%), sadness(22%), and fatigue (24%),and increased peacefulness(23%) and vitality (10%). Thesepercentages are improvementsfrom baseline and were statisticallysignificant.
There was also a reductionin stress symptoms, includinganxiety (21%), sleeplessness(24%) and rapid heartbeats(19%). Organizational qualityassessment revealed gains ingoal clarity (9%) and productivity(4%). These changes werenoteworthy in light of the majororganizational challengesfaced by the participants, andthe short time in which theimprovements took place.
In a second study, a cohortof police officers trained inHeartMath techniques demonstrateddecreased stress, negativeemotions, and fatigue, aswell as increased calmness andclarity under the acute stress ofsimulated police calls. Theyalso showed more rapid recalibrationto non-stress autonomicfunction following high stressscenarios, compared toan untrained control group(McCraty et al. 1999).
The findings have significantimplications for all of usin the medical profession, giventhe constant, intense stress weface in our work. What if youand your staff could lowerstress while increasing performance?All it really takes ispractice.
Practical Applicationof Heart Rate
There are several systems nowavailable for home and officeapplication of Heart Rate Variability monitoringand emotional shifting.The Freeze Framer® is commerciallyavailable throughHeartMath.com and utilizesHeart Rate Variability to aid people in emotionalentrainment. The concept issimple; Freeze Framer® tutorialsteach various emotionalshifting techniques, such asQuick Coherence. The softwareanalyzes Heart Rate Variability through a fingerclip pulse sensor. HeartMathrecently introduced an ear clipsensor that allows users to havetheir hands free while monitoringHeart Rate Variability.
The program also comeswith fun games powered by theuser’s ability to maintain coherentHRV patterns. The gamesinclude a black and white scenicpicture that gradually fillswith color, a hot air balloonthat takes flight, or a pot thatfills with gold, all by staying ina cohesive emotional state.HeartMath also teaches cliniciansthrough teleconferencing,how to use Freeze Framerin the office with patients.Another enjoyable newapplication of this technologyis The Journey to Wild Divine.This is a home computer“game" using HRV monitoringand skin conductance levels(SCL), both measured throughfinger sensors. In The Journey toWild Divine, a player navigatesthrough colorful and exotic virtualenvironments, learning touse his or her own physiologyas a guide. Certain game areasteach the player to relax, while others teach how to consciouslygenerate excitement andpositive emotions, makingfor a fun adventure that justso happens to provide effectiveautonomic entrainment(For more information, visitwww.wilddivine.com).
Emotional Intelligence
For a bit of icing on the physiologic cake, the state of coherent HRV patterning is also associated with enhanced cortical function. When one is in a state characterized by elevated catecholamines, elevated cortisol, and low HRV, cerebral cortex function is inhibited. The opposite is true when one is in a state characterized by low catecholamine levels and coherent HRV. You can therefore enhance your cortical function and emotional intelligence by practicing techniques that induce low catecholamine, high Heart Rate Variability physiology. These include emotional shifting, meditation, prayer and deep breathing.
The interaction between the autonomic nervous system and the heart is dynamic and bidirectional. While it is clear that emotional states affect HRV, it is equally true that changes in HRV can affect changes in emotions and cortical function. People can learn to control HRV, which in turn, brings many emotional and physiologic benefits. When one shifts from a state of frustration, anxiety, hostility or depression to a state of appreciation, caring or loving, the HRV shift is quite dramatic. Voluntary practices such as prayer or recitation of mantras positively affect HRV. The greatest effects occur when cyclic respiration is combined with entrainment of positive emotions. This will affect not only cardiovascular physiology, but also cortical function and perception.
Remind yourself and your patients that perception and cortical function are within our control. Whether through modern techniques like HeartMath or other applications of Heart Rate Variability and biofeedback, or through ancient spiritual practices including prayer, mantra practice, or meditation, it is possible to entrain coherent and harmonious psychophysiological states that will go a long way toward improving overall health and reducing risk for many chronic diseases.