Calming the Nervous System – Part 2: Introduction to Biofeedback

Part two of a three part education series exploring new ways to understand, measure, and manage our natural response to internal and external stressors.

“The nervous system holds the key to the body’s incredible potential to heal itself” - Sir Jay Holder, MD, DC, PhD

The operating system:

In part one we learned the basics of polyvagal theory, and the three subsystems of the autonomic nervous system (ANS):

“Rest and Digest” - Parasympathetic Nervous System (PNS)

“Fight or Flight” - Sympathetic Nervous System (SNS)

“Numb and Glum” - Unmyelinated Vagus of the Parasympathetic Nervous System (UVPNS)

We often view emotions as complex, outside of our control, and even difficult to define.  The truth is that our emotions are responses to internal and external stimuli, and our nervous system responds accordingly to the perceived threat.  Think about the nervous system as the operating system for a computer or smartphone. The operating system runs in the background so we can scroll through social media apps, search the internet, and talk with friends.  However, the operating system has vulnerabilities and can crash, especially if we are not monitoring the computer’s overall performance. Perhaps a virus infects the registry, the system is five updates behind, or the processor is damaged.  While we still understand how to search the internet, we may not have the ability to do so - sounds frustrating.

We can assess our human operating system and make effective adjustments using biofeedback. 

 The relationship of biofeedback to mental health:

Biofeedback is a process that involves receiving information about the body.  Applied biofeedback is the monitoring and exerting of influence to produce a change in the incoming information.  Essentially, biofeedback is a more scientific and quantitative measurement to the effectiveness of any psychiatric intervention.  So how does it work?

 Many people have learned deep breathing techniques that can temporarily regulate the heart’s natural modulation.  For example, as we breathe in the heart rate increases and as we breathe out the heart rate decreases. When breathing in there is more pressure around the heart and lungs.  This increase in pressure makes it difficult for the brain to sense blood pressure, and thus makes it difficult for the brain to regulate blood pressure. While breathing in, just in case, the brain increases the heart rate momentarily.  When breathing out there is less pressure around the heart and lungs, and the brain has an easier time sensing and regulating blood pressure. So, when breathing out the brain can readily regulate the heart rate based on what it senses.  

In the Connection or “Rest and Digest” phase there is a larger variability in heart rate between breathing in and breathing out.  However, when we are in the Adrenaline or “Fight or Flight” state there is potentially little to no variability in heart rate. Many psychiatric disorders are associated with low variability in heart rate.  Increasing variability in heart rate has been associated with better psychiatric and mental health prognosis and outcomes. 

 Respiratory Sinus Arrhythmia (RSA):

Respiratory Sinus Arrhythmia (RSA) has been shown to be a valid and reliable biomarker of emotional regulation in humans, and RSA is an index of the parasympathetic nervous system’s (PSNS or Connection “Rest and Digest”) ability to mediate cardiac control.  RSA has become increasingly popular in psychological research as the biomarker can be measured non-invasively. Emerging evidence suggests that low RSA and excessive RSA reactivity are indications of prefrontal cortex dysfunction. Prefrontal cortex dysfunction is associated with specific disease processes including anxiety, phobias, panic disorders, inattentiveness, autism spectrum, antisocial traits, depression, self injurious behavior, and irritability.  We want high RSA. High RSA indicates increased executive control over behavior, which characterizes the goal of most forms of treatment.

RSA’s relationship to Heart Rate Variability (HRV):

There are different ways to quantify RSA, which can be divided into two main categories; time-domain and frequency-domain.  Time domain measures are calculated by the time between R peak intervals on an ECG reading. Frequency domain divides the heart rate signal into low and high frequency bands.  High frequency is driven by the PSNS, and low frequency is driven by both the Sympathetic Nervous System SNS and PSNS. A single gold-standard measure between time and frequency domains has not yet been decided on within the psychology research community.  However, many researchers, clinicians, and healthcare consumers have leaned into the frequency domain measurement of Heart Rate Variability (HRV) as an accessible, affordable, and valid biomarker. HRV provides direct insight into autonomic nervous system tone, and has a well-established role as a marker of cardiovascular risk. 

  Biofeedback using HRV:

Individuals with high HRV tend to have better emotional well-being than those with low heart rate variability, but the mechanisms of this association are not yet clear.  Recent studies using daily biofeedback sessions to increase the amplitude of heart rate oscillations suggest that high amplitude physiological oscillations have a causal impact on emotional well-being. Because blood flow timing helps determine brain network structure and function, slow oscillations in heart rate have the potential to strengthen brain network dynamics, especially in the medial prefrontal regulatory regions that are particularly sensitive to physiological oscillations.

So what can we do to increase HRV and improve our mental health.  Everyone is a snowflake, and the exercise or relaxation technique or therapy that works for one person may not work for another.  For example, moving from a panic attack in the Adrenaline phase to a calm state of mind in the Connection phase requires a different skill set than moving from not being able to get out of bed in the Shutdown phase to improved motivation in the Adrenaline phase.  The goal is to spend more time being present, compassionate, curious, grounded, and joyful. Working to improve HRV through biofeedback can help accomplish this goal.  

Real-time HRV and other biofeedback apps are available for download on the App Store or Google Play.  We recommend the free app Elite HRV: 

(Pictures here)

Compatible biofeedback monitors for Elite HRV can be found here:

https://elitehrv.com/compatible-devices

Hernando et al. (2018) endorse the Apple Watch as a viable option for HRV biofeedback monitoring.  Accoring to Apple, the Apple Watch calculates HRV by using the standard deviation of beat-to-beat measurements which are captured by the heart rate sensor.  Apple stresses, their HRV design is only validated for users over the age of 18. Third party apps and devices, like Elite HRV and the compatible devices listed above, can also add HRV to the Apple app, Health.  

Instructions on how to monitor HRV on Apple Watch can be found here: Apple Watch HRV

HRV is influenced significantly by age, sex, race, physical fitness, clinical conditions, sleep and wake cycles and drug treatment.  In part three of this educational series we’ll explore specific ways to increase HRV and control our response to internal and external stressors based on whether we need to move from Shutdown to Adrenaline or Adrenaline to Connection.

References:

Campbell, A. (2017). Respiratory sinus arrhythmia and PTSD: A meta-analysis. Retrieved from: http://libres.uncg.edu/ir/uncg/f/Campbell_uncg_0154M_12310.pdf

Lexicomp (2019). Evaluation of heart rate variability. Retrieved from: https://www.uptodate.com/contents/evaluation-of-heart-rate-variability?search=RSA&source=search_result&selectedTitle=1~3&usage_type=default&display_rank=1

Pruder M.D., D.; Ing M.D., K; Borecky, A. (2018). “Emotional shutdown: Understanding polyvagal theory”. Psychiatry & Psychotherapy Podcast. 9 July 2018. https://psychiatrypodcast.com/psychiatry-psychotherapy-podcast/polyvagal-theory-understanding-emotional-shutdown

Hernando et al. (2018). Validation of the Apple Watch for heart rate variability measurements during relax and mental stress in healthy subjects. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6111985/