On the importance of HRV during long Covid

HRV-Insight: Why HRV can make a decisive difference even with long COVID!

In our HRV Insight series, the CEO and medical director of Autonom Health GesundheitsbildungsGmbH, Dr. Alfred Lohninger, treats and documents various HRV topics, including current HRV research areas. In this blog post, we want to address the highly topical subject of Long COVID.
We have studied the latest research on the subject of Long COVID in detail, are in contact with recognized experts on the subject and have been able to identify highly interesting patterns in HRV through “COVID measurements” in our own database. In the following, we would like to provide a brief outline of the current state of knowledge.
The above statements quote from the German and Austrian guidelines, refer to the most important scientific studies currently available and provide an insight into the explanations being discussed for the development and treatment of Long COVID.

WHAT IS LONG OR POST COVID?

To date, there is still no generally accepted definition of long/post Covid. Both the World Health Organization (WHO) and the CDC (Centers for Disease Control and Prevention) and the RKI are based on the proposal of the British National Institute for Health and Care Excellence (NICE).
This states: “The essence of the disease is that – similar to other infectious diseases – persistent symptoms occur after a SARS-CoV-2 infection and after vaccination against the pathogen.
Beyond a period of four weeks from infection, these are referred to as long COVID and, if they persist for more than twelve weeks, as post-COVID syndrome .

Fig. 1: June 2022: The gut microbiome, the abdominal brain and the vagus seem to play an important role.
Source: Bostick, et al (2022). Gut microbiome-mediated regulation of neuroinflammation. Curr Opin Immunol. 2022 Apr 21;76:102177. doi: 10.1016/j.coi.2022.102177.

Causes

The exact causes are not yet known.
The persistence of the virus or the whereabouts of components of the virus in the body can play a role. Possible mechanisms are tissue structures destroyed by Covid 19. These include damage to the inner lining of blood vessels and the resulting circulatory and blood clotting disorders, malfunctions of the immune system and even autoimmune reactions, excessive inflammatory reactions, fluid and mineral imbalances and potential side effects of COVID-19 therapy. The persistence of components of the virus in the body over weeks and months can play a significant role.

HOW OFTEN DOES LONG COVID OCCUR?

After studying 23 reviews, i.e. scientific publications that summarize the current state of research, and 102 original papers, i.e. research papers with the aim of gaining new insights, the Robert Koch Institute (RKI) came to the following conclusion: Adults who did not have to be hospitalized for Covid 19 suffered between 7.5% and 41% of long-term consequences. In hospitalized adults, long-term health effects were reported in 37.6%.

HOW DOES THE DISEASE PROGRESS?

All three parts of the autonomic nervous system– the sympathetic nervous system, the parasympathetic nervous system and the enteric nervous system – obviously play a definite role in the course of Long COVID. Dysautonomia as a central pathophysiological mechanism is becoming an important signpost for research:

Die Rolle des Autonomen Nervensystems bei Long COVID — Fig. 2: The role of the autonomic nervous system in Long COVID. Modified after Illustration of the pathophysiological mechanisms underlying Post-COVID-19 syndrome. From: Julia Aranyo, et. al. “Inappropriate sinus tachycardia in post-COVID-19 syndrome”. Source: Autonom Health

The virus leads to DYSFUNCTION of organs
The dysfunction affects the enteric, parasympathetic and sympathetic nervous systems and leads to DYSAUTONOMY
Persistent dysautonomy leads to EXHAUSTION or OVEREXERCISE
Fear, insecurity and being let down reinforce DYSAUTONOMY
Dysautonomy leads to further DYSREGULATION of organ functions
The dysregulation of organ functions and dysautonomy cause Long COVID SYMPTOMS
Dysautonomy changes the HEART RATE VARIABILITY

Diagnosis

The diagnosis of long/post COVID syndrome cannot be diagnosed or objectified by a single laboratory test or by a panel of laboratory values. Nor do normal laboratory values rule out long/post COVID syndrome. Long COVID is therefore actually diagnosed clinically, i.e. on the basis of symptoms.

Symptoms

A distinction is made between a variety of symptoms. A not insignificant proportion of the most common ones can be clearly detected with HRV.
These are:

1. performance and activity impairment in the sense of a characteristic exertion-induced worsening of symptoms
2. shortness of breath and shortness of breath (at rest and on exertion)
3. non-restorative sleep/sleep disorders
4. altered breathing pattern
5. stress
6. tachycardia

Common symptoms that cannot be detected with HRV:

7. headache
8. loss of smell, odor disorders, changes in taste
9. cough
10. depressive mood
11. fear
12. symptoms of post-traumatic stress disorder
13. pain of a general nature
14. Cognitive limitations
15. compulsive actions
16. hair loss

HRV Spektrogramm Long Covid — Fig. 3: A 43-year-old patient who falls into a massive state of exhaustion during a walk and for three hours afterwards. Remarkably, in contrast to burnout, sleep is very good. Source: Autonom Health

Abb. 4: Die Darstellung des Atemfrequenz-Verlaufs im HRVmed-Analyseportal. Quelle: Autonom Health — Fig. 4: The representation of the respiratory rate curve in the HRVmed analysis portal. Source: Autonom Health

Leading symptom

Patients with long/post COVID very frequently report the symptom “fatigue” as the most common, most significant and therefore the leading symptom. It also occurs after a number of other viral illnesses and is known as chronic fatigue syndrome or chronic exhaustion syndrome . It is clear to anyone familiar with vegetative function diagnostics that the two terms should not be used interchangeably.

Exhaustion characterizes the complete breakdown of autonomic regulation, recognizable by the decrease in HRV in all frequency ranges by more than 85 percent compared to the daily average, with a simultaneously too high heart rate, over large to entire parts of the measurement, and / or also as a stimulus inadequate decline, i.e. with relatively low stress. In contrast to burnout syndrome, the signs of exhaustion in long COVID also occur during good to very good sleep.

Fatigue, on the other hand, must be recognized as a vegetative appeal, with an increase in HRV, especially in the HF range, the pNN50, the occurrence of RSA during the day and low heart rates. The vagus switches on, switches to rest, resynchronization of breathing and heartbeat, in order to bring as many of the self-organized, rhythmically interacting processes in us into order in the truest sense of the word, as it always does to counteract inflammatory processes. An extremely sensible phenomenon that has been prominently published scientifically for 20 years as the Inflammatory Reflex.

The role of the vagus in Long COVID is becoming increasingly important as research progresses. It is recognized as a vehicle for the entry of virus (components) into the brain, as a sometimes functionally and even structurally damaged nerve, but also as overactivated in those affected by Long COVID. The concept of vagus imbalance, which has recently emerged in the literature, may hold the key to a differentiated diagnosis and treatment of long COVID.

Abb. 5: Eine mögliche Rolle des Vagus bei Long COVID. Quelle: Dani, et al. Autonomic dysfunction in ‚long COVID‘: rationale, physiology and management strategies. Clin Med (Lond). 2021 Jan;21(1):e63-e67.doi: 10.7861/clinmed.2020-0896. Epub 2020 Nov 26. — Fig. 5: A possible role of the vagus in Long COVID. Source: Dani, et al. Autonomic dysfunction in ‘long COVID’: rationale, physiology and management strategies. Clin Med (Lond). 2021 Jan;21(1):e63-e67.doi: 10.7861/clinmed.2020-0896. Epub 2020 Nov 26.

Parallels to burnout

Similar to burnout, there appear to be two forms of long COVID: A classic form in which the vegetative system switches to “stand-by mode” and shuts down both the ergotropic and trophotropic systems. This means that both the sympathetic and parasympathetic nervous systems are inactive and waiting for a “restart”, as described in the literature:

Fig. 6: HRV, dysautonomia and long COVID. Source: Sha, et al (2022). Heart rate variability as a marker of cardiovascular dysautonomia in post-COVID-19 syndrome using artificial intelligence. Indian Pacing Electrophysiol J. Mar-Apr 2022;22(2):70-76. doi: 10.1016/j.ipej.2022.01.004. Epub 2022 Jan 29.

Abb. 7: Long COVID Patientin mit Indikatoren für Erschöpfung. Quelle: Autonom Health — Fig. 7: Long COVID patient with indicators of fatigue. Source: Autonom Health

The second form is possibly rooted in the “Inflammtory Reflex“.
The mechanism first described by Kevin J. Tracey in 2002 in the scientific journal “Nature” is based on actylcholine, the transmitter substance of the vagus nerve as a molecule directed against inflammation – which is undoubtedly always present in long COVID.
On the other hand, there is a conceivable correlation between the fact that a particularly large number of women and younger people are affected by Long COVID and the fact that these groups of people inherently have the highest vagotonicity. Both our experience and publications sometimes also describe an abnormally high vagal tone in long COVID patients in the sense of a vagal rigidity that aims to create an environment to enable self-healing processes.

A mechanism that aims to use the existing vegetative potential to contain ongoing inflammatory processes.
Numerous symptoms of Long COVID as well as the sudden occurrence of high heart rates with the slightest exertion POTS (Postural Orthostatic Tachycardia Syndrome) can be explained in this way.

Fig. 8: HRV, unnaturally high parasympathetic dominance and long COVID symptoms. Source: Asarciklli, et al. Heart rate variability and cardiac autonomic functions in post-COVID period. J Interv Card Electrophysiol. 2022 Feb 1;1-7. doi: 10.1007/s10840-022-01138-8.

WHY ARE SO MANY YOUNG PEOPLE AFFECTED?

It is also obvious to us that Long COVID generally – and probably in this form of vagus overactivation) – occurs in younger people, especially women, as they have the highest vagal tone:

Abb. 9: Anteil der High Frequency Power der HRV bei 20- bis 60-jährigen Männern und Frauen. Quelle: Alfred Lohninger,Herzratenvariabilität: Das HRV-Praxislehrbuch, 2. überarbeitete Aufl. 2021, Seite 264 — Fig. 9: Proportion of high frequency power of HRV in 20- to 60-year-old men and women. Source: Alfred Lohninger,Heart Rate Variability: The HRV Practice Textbook, 2nd revised ed. 2021, page 264

Medication

Drugs that have been and are successfully used to treat Long COVID, namely amphetamines, antiepileptics, antihistamines, selective serotonin and selective serotonin-noradrenaline reuptake inhibitors, noradrenergic and specific serotonergic antidepressants, stimulants and drugs for Parkinson’s disease, inhibit noradrenaline reuptake or promote its release, thus increasing sympathetic tone. Or they have an anticholinergic effect and thus reduce vagal tone. Any medication used could ultimately serve to resolve the vagal rigidity.
The fulfillment of the desire to discover a highly effective drug against all forms of long COVID, whether due to pressure from those affected or fueled by the hopes of researchers, will be a major challenge for researchers.

Therapy

Chronic fatigue syndrome caused by long COVID naturally follows different treatment principles than chronic fatigue syndrome. The therapeutic principle of pacing has proven to be not only effective but also indispensable in both forms. It states that it is necessary to use one’s own resources sparingly and to strictly avoid overloading them. The aim is to minimize the frequency and severity of relapses (“crashes”). The less attention is paid to pacing and the more patients are encouraged to increase their level of activity, the longer the relapses or crashes. In addition, there is a risk that the general condition will deteriorate due to overloading and that the patient’s quality of life will be further reduced as a result.

Prof. Dr. med. Carmen Scheibenbogen, Charité Berlin, has been researching and treating patients with chronic fatigue syndrome for many years.
She has set up a post-Covid outpatient clinic at Berlin’s Charité hospital and summarizes the importance of pacing for those affected as follows: “Everyone has to find their current limit and stay below it for a certain period of time. If you take this to heart from the outset, it increases the chance that the disease will heal.“

Finding your own limits is easy with the My Autonom Health App is very easy. A performance test as part of a 24-hour measurement, e.g. running or walking as far as possible for 30 minutes or less, defines the personal current stress levels. These, including the pulse level at which the limit range begins, are often surprisingly low. Any excess, even with a heart rate of e.g. 105 bpm in a young, athletic person who is affected by Long COVID, leads almost immediately to a sharp drop in total power compared to the daily average. If you always stay below your current crash limit with ongoing support from the My Autonom Health app, the likelihood of a full recovery increases significantly.

Abb. 10: Die Funktionskreise des Autonomen Nervensystems. Quelle: Autonom Health — Fig. 10: The functional circuits of the autonomic nervous system. Source: Autonom Health

Long Covid Care by Autonom Health

The Long COVID Care Program developed by Autonom Health, described in the chapter above, enables classification into the respective form of dysautonomia. The distinction between chronic fatigue syndrome and fatigue syndrome enables differentiated therapy strategies to be developed in personal coaching with specially qualified HRV professionals in the form of an individual recovery plan. Jour Fixe to impart and discuss specific knowledge and the exchange in the Autonom Health Community offer those affected individual support and round off the unique care program.