HRV Demographics, Part 3 – Health, Medication & Guidelines

In this third part to the HRV Demographics series, we will cover two of the biggest health factors and research on some of the common diseases that affect heart rate variability, as well as how medication can alter your HRV values and potentially cause them to be incomparable to your relevant demographics.

In case you missed them, Parts 1 and 2 lay the foundation for this discussion:

• Part 1 – Age & Gender
• Part 2 – Fitness Level Demographics

HRV Connection to Health and Disease

A growing number of studies analyzing cardiovascular, respiratory, gastrointestinal, mental health diseases, and various other pathological conditions show that Heart Rate Variability can significantly decline with decreased health. In fact, changes in Heart Rate Variability have been correlated with 9 out of the 10 leading causes of death in the United States, including:

• Heart disease
• Cancer
• Chronic lower respiratory diseases
• Stroke (cerebrovascular diseases)
• Alzheimer’s disease
• Diabetes
• Influenza and pneumonia
• Nephritis, nephrotic syndrome, and nephrosis
• Intentional self-harm (suicide)

Autonomic Imbalance Linked to Disease

There is growing evidence for the role of the autonomic nervous system (ANS) in a wide range of diseases such as those mentioned above. Autonomic imbalance as assessed via HRV measurement is associated with increased morbidity and mortality for these various pathologies. Autonomic imbalance is the imbalance between the Parasympathetic and Sympathetic branches of the ANS usually with a Sympathetic predominance and can be assessed by lower HRV indices.

Furthermore, HRV has been shown to accurately predict mortality in cases of heart failure, cardiomyopathy, and renal failure.  In a study analyzing 808 post-myocardial infarction (heart attack) patients, HRV showed to be a significant independent predictor of mortality (Kleiger et al., 1987). In the study, Time Domain SDNN values were analyzed to predict survival rates of patients after a serious myocardial infarction episode. Patients with SDNN values above 100 showed a significantly higher survival rate. Survival rates declined as the Heart Rate Variability SDNN value decreased.

In a study analyzing 808 post-myocardial infarction (heart attack) patients, HRV showed to be a significant independent predictor of mortality (Kleiger et al., 1987).

HRV has also been shown to reflect autonomic neuropathy (nerve damage often linked to diabetes) in diabetic patients (Vinik A. I. et al., 2011). Even the pre-diabetic stage, where individuals have impaired glucose tolerance, is associated with lower HRV and decreased Parasympathetic activity. It is believed that Parasympathetic modulation may decline with an autonomic imbalance during the progression “from normal glucose tolerance to impaired glucose tolerance and finally diabetes” (Wu J. S. et al., 2007).

Autonomic imbalance and dysfunction is also commonly associated with terminally ill cancer patients (Walsh et al., 2002). Many studies have shown HRV indices are considerably lower for cancer patients than the general population. In a study analyzing 68 cancer patients, Heart Rate Variability showed to decrease in terminally ill cancer patients with the progression of the illness and SDNN was determined to be “useful in predicting survival duration” (Kim DH et al., 2010).

Lower HRV and autonomic imbalance has also been correlated to epileptic conditions, respiratory diseases, Alzheimer’s, and a growing number of other pathologies. It has even been used to predict epileptic episodes (Kolsal E. et al., 2014) and monitor disease progression.

HRV has not only been linked to the various diseases but also to many of the risk factors such as hypertension, obesity, stress, etc. associated with those diseases. Interestingly, HRV can also predict sudden death and cardiac death in apparently healthy individuals. This makes it even more powerful of a tool since HRV measures autonomic imbalance that can be used to predict health and mortality in both high risk and low risk populations.

HRV measures autonomic imbalance that can be used to predict health and mortality in both high risk and low risk populations.

Inflammation & Immune System

HRV has been associated with “immune dysfunction and inflammation, which have been implicated in a wide range of conditions including cardiovascular disease, diabetes, osteoporosis, arthritis, Alzheimer’s disease, periodontal disease, and certain types of cancers” (Thayer J. F. et al., 2009). This makes sense since autonomic imbalance, which we connected to disease in earlier discussion, is a marker of inflammation.

Autonomic imbalance is a marker of inflammation.

Some research suggests that autonomic dysregulation may lead to inflammation “providing a pathway through which traditional risk factors promote the development” of disease. (Vinik A. I. et al., 2011). Many others believe that inflammation actually alters Heart Rate Variability and causes the autonomic imbalance since it has been proven that sympathetic activation is pro-inflammatory.

No matter if it is the “chicken” or the “egg”, it is clear that inflammation and immune response are important factors that link to disease, affect health, and are correlated with Heart Rate Variability.

Inflammation

Inflammation is a localized reaction to physiological stressors encountered through infections or injury and is the body’s way of protecting itself and informing you of an issue. Systemic inflammation is at the heart of many modern health issues. From overly stressful work and living environments, to nutritional choices, to disrupted circadian rhythms, the factors that can contribute to systemic inflammation are vast in number.

Systemic inflammation is at the heart of many modern health issues. Increases in systemic inflammation from just about any source correlate with decreases in Heart Rate Variability.

Increases in systemic inflammation from just about any source correlate with decreases in Heart Rate Variability. On a positive note, that means that HRV can effectively be used as a guide when seeking to improve systemic inflammation as is demonstrated in several case studies on this site and as discussed further in the “Foundations of Heart Rate Variability” course.

Immune System Activation

Similar to inflammation, immune system activation is necessary for survival. In the short term, activation of the immune system can actually increase HRV. This is another reason that taking many readings over time is important for context. However, if there is sustained immune system activity, there is likely an underlying issue that will, on average, decrease your Heart Rate Variability over time.

One of the main culprits in chronic immune system activation is autoimmune activity. Autoimmune activity is when your body mistakenly attacks itself when it is seeking to eliminate other offenders. This is a good place to look if your HRV is inexplicably low compared to your age-gender-fitness demographic.

Emerging research is linking autoimmune activity to many diseases previously thought to be unrelated such as Alzheimer’s disease. Although there is a factor of genetic predisposition in relation to autoimmune diseases, the expression of these diseases is also strongly related to nutritional or environmental factors. New research is continually emerging linking inflammation and autoimmune response to gut health and nutritional deficiencies.

Emerging research is linking autoimmune activity to many diseases previously thought to be unrelated such as Alzheimer’s disease.

Mental Health

The psychological condition, or mental health status, of an individual is commonly overlooked when considering overall health. However, mental health and physical health are directly linked. If mental health conditions are not addressed, then overall health can suffer as a result.

“Foundations of Heart Rate Variability” course instructor, Greg Elliott, has hands-on experience with the effects of psychological health with his patients. As he discusses in this blog post, the psychological and mental aspect of health can actually prevent physical recovery from manifesting. In his experience, the psychological aspect of health can play such an important role that he devotes an entire module to this topic in the course.

Psychological conditions, such as depressive disorders, can not only inhibit physical recovery, but they can also directly lead to a reduction in Heart Rate Variability, the manifestation of new physical health issues, or even death.

Psychological conditions, such as depressive disorders, can not only inhibit physical recovery, but they can also directly lead to a reduction in Heart Rate Variability, the manifestation of new physical health issues, or even death.

A meta analysis of 28 studies indicates that “clinically diagnosed major depressive disorder” may be one of the most prominent risk factors for developing cardiovascular disease (Van Der Kooy et al., 2007). And in an additional meta analysis of 300,000 participants over a period of 2 to 29 years, Pan et al. estimated that almost 4% of stroke cases in the United States could be attributable to depression (Pan et al., 2011).

The psychological state of an individual can be dynamic and complex. Due to its close ties to the Autonomic Nervous System, HRV data can help give objective feedback on the impact of the psychological state on the overall health of the system. For example, in a pilot study evaluating cardiac surgery patients, the patients with depression displayed a reduced SDNN, RMSSD and HF power, “indicative of reduced cardiac vagal control.” (Patron et al. 2012)

Further, Daniel Quintana and Andrew Kemp write in “The relationship between mental and physical health: Insights from the study of heart rate variability” that, “otherwise healthy patients with psychiatric illness should consider cardiovascular risk reduction strategies including physical exercise, meditation, smoking cessation, and dietary changes – all of which are known to increase HRV – especially when treated with antidepressant medication” (Kemp, Quintana, 2013).

HRV can be used to measure future health and wellbeing. The links between psychological conditions, mental health, and physical health are very real. And psychological conditions can be some of the most complex scenarios to diagnose and treat. HRV can help guide a practitioner when treating psychological conditions.

The links between psychological conditions, mental health, and physical health are very real. And psychological conditions can be some of the most complex scenarios to diagnose and treat. HRV can help guide a practitioner when treating psychological conditions.

On a less severe scale, our mood and perception of daily stress can have a big impact on the cumulative state of our health.

Medication & Considerations

As discussed in Part 1, Part 2, and above, there are many biological and lifestyle factors that can influence HRV. It is also important to point out that certain factors can also artificially affect a person’s HRV values, making it difficult or impossible to accurately compare them to their demographic.

Medication is one of the most common artificial influencers of Heart Rate Variability. Certain medications, such as beta-blockers, have been shown to affect both time domain and frequency domain measurements.  This is why the more reliable research studies involving HRV analysis exclude participants that are taking certain medication types.

It is important to understand that because most medications treat symptoms instead of the underlying disease or illness, these medications might artificially increase HRV while masking the deeper autonomic function and health of an individual. In regard to medication, higher HRV values does not automatically mean that you are healthier. If you are taking a medication and your HRV is significantly lower or higher than your demographic, you should consider that your HRV might be artificially skewed.

It is important to understand that because most medications treat symptoms instead of the underlying disease or illness, these medications might artificially increase HRV while masking the deeper autonomic function and health of an individual.

Other factors such as acute stress from physical or emotional events can also cause immediate changes in HRV. This is why it is important to take accurate measurements as discussed in the next section.

How To Ensure Accurate Demographic Comparison

The body is in a constant state of flux in response to stressors and recovery processes. As such, there are many potentially confounding factors when quantifying the state of the body in any way. Even blood tests that are touted for their accuracy can be highly skewed by recent food choices, sleep status, or a number of other factors.

As mentioned previously, heart rate variability is very sensitive to acute physiological changes. Fortunately, HRV is not an invasive measurement and can be measured frequently (as opposed to blood lab work). In order to achieve the most accurate HRV comparison to your demographic, make sure to follow these steps:

1. Measure HRV first thing in the morning. This eliminates the majority of the potential acute stressors that could be experienced throughout the day which affect HRV.
2. Take several short measurements. One long HRV measurement can be very useful, especially in a clinical or research setting. For most people though, several shorter measurements of two to five minutes each will be more useful for analysis and comparison.
3. Measure on different days. The results from a single day are highly dependent upon what activities you did the previous day, what you ate, how you slept, and many other short term factors. By taking a short reading each morning on (ideally) consecutive days, you can take the average of these HRV numbers and obtain a much more accurate picture of your overall health status.
4. Measure in the same position with a stable, resting heart rate. If you are able to take several measurements, make sure that your body is in the same position each time. Also, make sure that your heart rate has stabilized after getting into position but before starting the measurement. HRV is sensitive enough to be altered by relatively small changes in the angle of your back or the position of your arms and legs. Eliminate these variables by finding a comfortable and repeatable position.

Takeaway

There are many factors that contribute to systemic health and wellbeing and health status can markedly affect Heart Rate Variability values. Risk factor conditions and disease onset lowers HRV indicating autonomic imbalance. The good news is that many of these diseases can be prevented through adequate diet, exercise, and stress management and HRV can be used as a tool to monitor and guide.

Medication and other factors can artificially skew HRV values, making them not comparable between individuals. This should be considered when using HRV demographic data.

Also, prudent measurement is important to ensuring accurate HRV values for better comparison.

In Part 1 and 2 of this series, we provided HRV values for different age, gender, and fitness demographics to help you identify where you stand in comparison to your peers. However, in Part 3, we aimed to provide some understanding for why your HRV values might be above or below your demographic average. In Part 3, we do not present HRV values along with the research conclusions because disease type, level of onset of disease, and treatment program that affect health status can widely vary, as reflected in HRV indices, making them not easily comparable. HRV in relation to health status and medication needs to be evaluated on a case by case basis with the guidance of a clinician or appropriate health practitioner. If you have health conditions, or are unsure if you have underlying health conditions, this information might give you a good starting point for what to expect – especially in comparison to your normal demographic values presented in Part 1 and Part 2.

>>For a much deeper look at how to accurately measure, analyze, and directly impact your HRV values, check out the “Foundations of Heart Rate Variability” course. The course also covers, in much greater depth, the significance behind each of the HRV values such as HF, LF, SDNN, SD1, etc. and what to consider if specific values are off.

References:

Kemp, Andrew H., and Daniel S. Quintana. “The Relationship between Mental and Physical Health: Insights from the Study of Heart Rate Variability.” International Journal of Psychophysiology 89.3 (2013): 288-96. Web.

Kim, D. H., Kim, J. A., Choi, Y. S., Kim, S. H., Lee, J. Y., & Kim, Y. E. “Heart Rate Variability and Length of Survival in Hospice Cancer Patients.” Journal of Korean Medical Science, 25(8) (2010): 1140–1145. https://doi.org/10.3346/jkms.2010.25.8.1140

Kleiger, Robert E., J. Philip Miller, J. Thomas Bigger, and Arthur J. Moss, and the Multicenter Post-Infarction Research Group. “Decreased Heart Rate Variability and Its Association with Increased Mortality after Acute Myocardial Infarction.” The American Journal of Cardiology 59.4 (1987): 256-62.

Kolsal, Ebru, Ayşe Serdaroğlu, Erman Çilsal, Serdar Kula, Azime Şebnem Soysal, Ayşegül Neşe Çıtak Kurt, and Ebru Arhan. “Can Heart Rate Variability in Children with Epilepsy Be Used to Predict Seizures?” Seizure 23.5 (2014): 357-62. Web.

Kooy, Koen Van Der, Hein Van Hout, Harm Marwijk, Haan Marten, Coen Stehouwer, and Aartjan Beekman. “Depression and the Risk for Cardiovascular Diseases: Systematic Review and Meta Analysis.” Int. J. Geriat. Psychiatry International Journal of Geriatric Psychiatry 22.7 (2007): 613-26. Web.

Pan, An, Qi Sun, Olivia I. Okereke, Kathryn M. Rexrode, and Frank B. Hu. “Depression and Risk of Stroke Morbidity and Mortality.” Jama 306.11 (2011): 1241. Web.

Patron, Elisabetta, Simone Messerotti Benvenuti, Giuseppe Favretto, Carlo Valfrè, Carlotta Bonfà, Renata Gasparotto, and Daniela Palomba. “Association between Depression and Heart Rate Variability in Patients after Cardiac Surgery: A Pilot Study.” Journal of Psychosomatic Research 73.1 (2012): 42-46. Web.

Thayer, Julian F., Shelby S. Yamamoto, and Jos F. Brosschot. “The Relationship of Autonomic Imbalance, Heart Rate Variability and Cardiovascular Disease Risk Factors.” International Journal of Cardiology 141.2 (2010): 122-31.

Vinik, A. I., R. E. Maser, and D. Ziegler. “Autonomic Imbalance: Prophet of Doom or Scope for Hope?” Diabetic Medicine 28.6 (2011): 643-51.

Walsh D, Nelson KA. Autonomic nervous system dysfunction in advanced cancer. Support Care Cancer 10 (2002): 523–528.

Wu, Jin-Shang, Yi-Ching Yang, Thy-Sheng Lin, Ying-Hsiang Huang, Jia-Jin Chen, Feng-Hwa Lu, Chih-Hsing Wu, and Chih-Jen Chang. “Epidemiological Evidence of Altered Cardiac Autonomic Function in Subjects with Impaired Glucose Tolerance But Not Isolated Impaired Fasting Glucose.” The Journal of Clinical Endocrinology & Metabolism 92.10 (2007): 3885-889.