What is Heart Rate Variability (HRV) Biofeedback?
Heart Rate Variability (HRV) biofeedback is a relatively new technique for training people to change the variability and dominant rhythms of their heart activity. The use of HRV biofeedback began in Russia in the early 1980s where it was applied to the treatment of asthma and numerous other conditions. Research is now going on in many sites in the United States and Canada and other countries, applying HRV biofeedback techniques to a variety of medical and psychiatric conditions, including: anger, anxiety disorders, asthma, cardiovascular conditions includinmg heart failure, chronic obstructive pulmonary disorder (COPD), depression, irritable bowel syndrome (IBS), chronic fatigue, and chronic pain.
What is Heart Rate Variability?
Heart rate variability (HRV) is a measure of the continuous interplay between sympathetic and parasympathetic influences on heart rate that yields information about autonomic flexibility and thereby represents the capacity for regulated emotional responding.
Effective emotional regulation depends on being able to flexibly adjust your physiological response to a changing environment. HRV reflects the degree to which cardiac activity can be modulated to meet changing situational demands.
To view a brief YouTube video on the mysteries of the emotional heart...
The sympathetic (SNS) and parasympathetic (PNS) branches of the autonomic nervous system (ANS) antagonistically influence the lengths of time between consecutive heartbeats. Faster heart rates, which can be due to increased SNS and/or lower PNS activity, correspond to a shorter interbeat interval while slower heart rates have a longer interbeat interval, which can be attributed to increased PNS and/or decreased SNS activity.
The frequency-based HRV analyses are based on the fact that the variations in heart rate produced by SNS and PNS activity occur at different speeds, or frequencies. SNS is slow acting and mediated by norepinephrine while PNS influence is fast acting and mediated by acetylcholine.
Physiologic Underpinnings of HRV
Breathing air into the lungs temporarily gates off the influence of the parasympathetic influence on heart rate, producing a heart rate increase. Breathing air out of the lungs reinstates parasympathetic influence on heart rate, resulting in a heart rate decrease. This rhythmic oscillation in heart rate produced by respiration is called respiratory sinus arrhythmia.
The central autonomic network (CAN) assists emotional regulation by adjusting physiological arousal to appropriately match the external and internal environments. The CAN consists of cortical, limbic, and brainstem components. Its output is transmitted to the sinoatrial node of the heart, among other organs.
HRV reflects the moment-to-moment output of the CAN and, by proxy, an individual’s capacity to generate regulated physiological responses in the context of emotional expression.
Psychophysiological Theories of HRV
Two major theories causally relate autonomic flexibility, represented by HRV, and the capacity for regulated emotional responding:
- Polyvagal Theory: an evolutionary explanation that the ANS developed in stages to deal with changes in the environment and respond effectively. The last component developed, the ventral vagus complex, physically connects with the facial muscles, voice production, and other socially important behaviors, which creates a physical connection between the heart and emotional expression.
- Neurovisceral Integration Theory: an integrative explanation that evolutionary forces led to the development of a rapidly responding vagus nerve to support appropriate emotional expression and regulation through connections with the cortex, limbic system, and brainstem. By inhibiting other potential responses through synaptic activity in the brain and vagal activity in the body, the CAN acts as a “neurophysiological command center governing cognitive, behavioral, and physiological elements into regulated emotion states”.
Both theories presented above are similar in that they (a) specify a critical role for parasympathetically mediated inhibition of autonomic arousal in emotional expression and regulation and (b) maintain that HRV measures are informative about individuals’ capacity for this aspect of regulated emotional responding.
To view a brief "Greater Good Science" YouTube Video with Dacher Keltner speaking the amazing vagus nerve and how it affects human behavior...
Empirical Research With HRV
- Low HRV is an independent risk factor for several negative cardiovascular outcomes
- Low HRV is a proxy for underlying cardiovascular disease processes, including hypertension, ventricular arrhythmia, chronic heart failure, and ischemic heart disease
- Higher levels of resting HRV have been associated with effective stress coping strategies
and increased resilience under stress
- Attention control is associated with higher HRV
- Reduced HRV is seen in many disorders with autonomic dysregulation, including anxiety, depression, irritable bowel syndrome, and asthma
- Patients with generalized anxiety disorder show lower HRV than controls
- Patients with major depression show lower HRV than controls
- Reduced HRV is associated with increased vulnerability to physical and psychological stressors and disease
- HRV indexes adaptibility and greater HRV represents more efficient regulation of blood pressure, heart rate, and respiratory gas exchange
Summary, Future Directions, and Conclusions
HRV is emerging as an objective measure of individual differences in regulated emotional responding, particularly as it relates to social processes and mental health.
Clinical applications of HRV also exist. For example, increasing an individual’s capacity for inhibitory emotional regulation through HRV biofeedback may have therapeutic implications for mood, anxiety, and impulse control disorders.
Unlike other psychophysiological variables, HRV provides information regarding both PNS and SNS activity, thereby permitting inferences about both inhibitory and excitatory processes in emotion regulation.
What is Resonant Frequency Training?
Resonant Frequency Training is a specific variation of Heart Rate Variability biofeedback.
Current research suggests that every individual has a “resonant frequency” at which heart rate variability is the greatest, and this resonant frequency can be measured with biofeedback instruments. While there is no uniform or ideal for all persons, this resonant frequency is most often produced by a persons in a relaxed mental state, with positive emotional tone, breathing diaphragmically and smoothly at a rate of about 4 to 7 breaths per minute (includes 99% of population; 5 to 6 b/m in approximately 50% of population). Relaxed breathing at about 6 b/m produces a spike of heart rate variability at about 0.1 Hz and tends to maximize most other measures of heart rate variability in most people. That said, finding the specific breathing rate that will absolutely maximize heart rate variability measures for each individual patient (i.e., their individual Resonant Frequency) and training them to breathe diaphragmically at their Resonant Frequency will maximize clinical effects. In this regard, the average person will improve their psychophysiological balance by breathing at 5 to 6 b/m but may obtain even greater gains by finding their exact Resonant Frequency— be it 5.7, 6.2 or 4.4 b/m— and using this breathing rate during HRV practice.
Heart Rate Variability as a Measure of Stress
Research has shown that our emotions are reflected in our heart rhythm patterns. The analysis of heart rate variability, or heart rhythms, is well-recognized as a powerful, non-invasive, and relatively simple measure of neuro-cardiac function that reflects heart-brain interactions and basic autonomic nervous system dynamic balance, which are especially sensitive to changes in emotional state.
Heart Rate Variability (HRV) is a measure of the naturally occurring beat-to-beat changes in heart rate. The sympathetic (SNS) and parasympathetic (PNS) branches of the autonomic nervous system (ANS) antagonistically influence the lengths of time between consecutive heart beats. Faster heart rates, which can be due to increased SNS and/or lower PNS activity, correspond to a shorter interbeat interval (i.e., the time between beats) while slower heart rates have a longer interbeat interval, which can be attributed to increased PNS and/or decreased SNS activity. When we are experiencing acute stress, there is a temporary increase in SNS arousal that activates our “fight or flight” response to help us deal with the demands of the stressful situation and, when the stressful situation is resolved or ended, there is a subsequent increase in PNS activity to turn off the stress response and bring us back into a more balanced state. With respect to heart rate, an acute stressor results in a SNS-driven stress response that increases our heart rate and, once the stress is over, the increasing PNS input should quickly bring the heart back to its normal, slower rhythm. Unfortunately, when stress becomes chronic or is driven by ongoing negative thoughts and emotions, we become stuck in SNS over-drive and the PNS becomes ever less effective in countering the SNS. In effect, our nervous system is running like a car on the highway that is being driven by a person who has the gas pedal floored at the same time as they are constantly applying the brakes. This type of driving will invariably cause the brakes to wear out and fail and will cause increased wear and tear on the engine and transmission.
Our heart rhythms are controlled by a number of factors but most powerfully by the interplay between the SNS and PNS branches of the autonomic nervous system. The SNS accelerates the heart; whereas the PNS acts as a brake a decelerates the heart. When the two systems are working in proper balance, the heart becomes exquisitely responsive to the body’s ever changing needs and yet maintains a strong underlying stability. When the two systems are not working well together, the heart shows a poor response to changing body needs and less stability in heart rate at rest. Chronic stress leads to autonomic imbalance with increased SNS activity and reduced PNS influence (Note: Imagine a powerful car with a very sensitive and twitchy gas pedal and very poor brakes.) and shows up as increased resting heart rate and reduced heart rate variability.
A long history of cardiac research tells us that low HRV is an independent risk factor for several negative cardiovascular outcomes and a valid proxy for underlying cardiovascular disease processes. Higher levels of resting HRV have been associated with more positive mood and outlook on life as well as more effective stress coping strategies. Attention control is associated with higher HRV. Persons suffering from generalized anxiety, depression, and chronic pain disorder show lower HRV than “normal” controls.
Biofeedback Training for a Healthy Heart
Healthy breathing is effortless, continuous, and slow. You mainly move air by expanding your stomach as you inhale and contracting it as you exhale. This allows the dome-shaped diaphragm muscle in your chest cavity to fully inflate your lungs, maintain an optimal level of carbon dioxide (CO2) in your blood, deliver needed oxygen to your body’s tissues, and increase the healthy variability of your heart.
What is respiratory biofeedback therapy?
Respiratory biofeedback therapy uses biofeedback instruments to enhance your awareness and control of rapidly-changing physiological responses. A therapist’s biofeedback instructions are guided by feedback provided by biofeedback devices. Respiratory biofeedback can help you learn to breathe effortlessly.
How does respiratory biofeedback measure your breathing?
In respiratory biofeedback, strain gauge sensors placed around your chest and stomach detect outward movement as you inhale and inward movement as you exhale. Biofeedback equipment can measure breathing depth and respiration rate.
Breathing depthor excursion is the difference between a stomach strain gauge’s outward and inward movement during each breathing cycle. In healthy breathing, the stomach effortlessly expands and contracts to more completely ventilate your lungs.
Respiration rateis the number breathing cycles that you complete each minute. In healthy breathing, you learn to slow your breathing down to 5-7 breaths per minute to increase the healthy variability in your heart rhythm and ensure sufficient CO2 in your blood.
Personal respiratory biofeedback training can teach you to increase your awareness of your breathing, to fill your lungs more completely, and to breathe slowly and continuously during everyday activities.
Which breathing problems can respiratory biofeedback correct?
Apnea, or breath-holding, is a common breathing behavior. Patients who exhibit apnea suspend their breathing during routine activities like talking or writing a check. Apnea disrupts the delivery of oxygen to your tissues, can make you feel starved for air, and can raise your blood pressure. A strain gauge can show stomach movement “flat-lines” during an apnea episode instead of showing regular waves of stomach expansion and contraction.
Biofeedback providers also use respiratory biofeedback to correct three problem breathing patterns:
Inthoracic breathing, your chest muscles expand and contract your ribs to move air. This inefficient pattern causes shallow rapid breathing, reduced ventilation of your lungs, less oxygen delivery to your tissues, minimal variability in your heart rhythm, and wasted energy.
In clavicular breathing, your accessory muscles raise and lower your chest and collarbones to move air. This pattern is often combined with chest breathing and exaggerates its problems.
In reverse breathing, your chest and stomach contract when you inhale and expand when you exhale. This pattern is also seen with chest breathing and also magnifies its negative effects.
What is effortless breathing?
Breathing is effortless when your body seems to breathe itself. Since effortless breathing feels like you are only using about 70% of maximum effort to fill your lungs, you may forget that you are breathing.
What are some effortless breathing tips for beginners?
You can quickly master effortless breathing if you:
- sit upright so that your stomach can relax
- wear clothing that allows your stomach to move freely
- breathe 5-7 breaths per minute
- exhale twice as long as you inhale
How does breathing affect your heart rhythm?
The autonomic nervous system controls your heart rhythm through its sympathetic and parasympathetic branches. The sympathetic branch accelerates your heart rate to prepare you for emergencies like fighting or fleeing snarling saber-toothed tigers. Think of the sympathetic branch as your heart’s gas pedal. In contrast, theparasympathetic branch slows your heart rate when you eat a meal. Think of the parasympathetic branch as your heart’s brake.
When you inhale, you take your foot off the parasympathetic brake and your heart rate accelerates. When you exhale, you press down hard on the parasympathetic brake and your heart rate slows. This rhythmic change in your heart rate is called heart rate variability (HRV). A simple measure of HRV is the difference between your fastest and slowest heart rate.
What else influences heart rate variability (HRV)?
Aerobic exercise and positive emotion can increase HRV. Aging, heart disease, physical inactivity, and negative emotion can reduce HRV. Chronic stress has a very strong negative effect on HRV.
How can you increase your heart’s healthy variability?
You can maximize heart rate variability (HRV) when you breathe from 4-7 breaths per minute because this combines the effects of your autonomic nervous system, blood pressure control system, and respiratory system on the variability of your heart rhythm. Researchers also believe that experiencing heartfelt emotions, like a parent’s love for a child, increases HRV.
How do biofeedback therapists monitor heart rate variability (HRV)?
In heart rate variability biofeedback, special instruments are used to detect your heart’s rhythmic contraction and relaxation. Clinicians use two biofeedback devices to monitor the heart. An electrocardiogram (EKG) uses sensors placed on your wrists and torso to detect the electrical signal generated by the heart. Alternatively, a photoplethysmograph (PPG) uses sensors placed on your earlobe or fingers to detect the pulse waves created by your heart’s pumping action.
HRV biofeedback can display both your breathing pattern and heart rhythm back to you to teach you to increase your heart’s healthy variability. You can learn to increase the difference between your fastest and slowest heart rate many times more than the average 3-5 beats-per-minute difference seen in adults.
How does increasing heart rate variability (HRV) protect your health?
Some researchers believe that HRV biofeedback instructions increase the balance between the two branches of the autonomic nervous system and that this can reduce your risk of dying from a heart attack.
How effective is HRV biofeedback therapy?
Biofeedback clinical trials have shown that HRV biofeedback techniques can help you control problems like anxiety, asthma, depression, high blood pressure, panic attacks, unexplained abdominal pain, and stress. HRV training is a promising form of stress management biofeedback for both children and adults.
Who should provide HRV training?
Biofeedback practitioners who are experienced in HRV biofeedback and certified by the Biofeedback Certification International Alliance (BCIA) are qualified to provide this training.
Is there insurance coverage for biofeedback?
Biofeedback reimbursement depends upon your insurance provider. Psychologists may code biofeedback services as psychotherapy to increase your chance of reimbursement.
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