HOW HEALTHY IS YOUR HEART - the insight into the inside

we are used to determining the health of our heart by the heart rate (HR)/ pulse rate, EKG and blood pressure. there is however one other determinant, hidden in the data we are already collecting, and has a great value for predicting our future state of heart as well as mental health. it is called the heart rate variability - HRV.

WHAT IS HRV

heart rate variability is the physiological phenomenon of variation in the time interval between heartbeats. it is measured by the variation in the beat-to-beat interval. other terms used include: "cycle length variability", "R–R variability", and "heart period variability".

HOW IS IT DIFFERENT THAN THE HEART RATE (HR)

the difference between the HR and HRV is that heart rate shows you how many times your heart beats in a minute, measured as beats per minute (bpm), whereas HRV shows you the time interval between two heartbeats, measured in milliseconds (ms). your HR may be 60 bpm, but it does not mean that the two heartbeats are followed in 1.0 second interval. one set of heartbeats may be at an interval of 1.3 seconds, whereas the next two may be at an interval of 0.7 seconds. this trait is presented by HRV. HRV is the HR affected by the activity of the autonomic nervous system (ANS).

bottom line: HRV gives you much more information about your health status. it addresses the heart and the nervous system. if we would compare it to the other health measurements it would be like comparing: xRAY to CBCT, blood glucose levels to glucose tolarance test, etc.

WHAT IS THE IMPACT OF HRV - WHY DOES IT MATTER SO MUCH??

HRV is an insight to the inside if your body. HRV is regulated by the ANS, so it provides indirect insight into autonomic nervous system tone, and it is a diagnostic tool, a non-invasive method in detection of autonomic health or impairment. it has a well-established role as a marker of cardiovascular health - it gives the information regarding the dynamics and mechanisms of cardiovascular regulation, as well as prediction of prognosis in several neurological disorders.

ANS has two branches: sympathetic and parasympathetic. while sympathetic branch is the stimulation/ activation/ fight- or - flight mode, the parasympathetic branch is the relaxation/ rest/ recovery mode of the body and mind. ANS works to maintain homeostasis and by examining ANS responsiveness to changes may indicate the body’s ability to tolerate or adapt to a new stimulus.

IT IS BETTER TO HAVE HIGH HRV. low HRV happens when your sympathetic arm of the ANS is dominating, leading to fewer variations between heartbeats. low HRV may thus indicate poor health that can contribute to mental health problems and some cardiovascular diseases. high HRV occurs when the parasympathetic arm of the ANS is more activated. in this state, you have more flexibility and resilience in switching between low and high heart rates, you are more adaptable to changes/ stimuli. high HRV may thus indicate better cardiovascular health and the ability to cope better with stressful situations. HRV levels are naturally changing during the day. but if a person is chronically stressed or overloaded – physically or mentally – the natural interplay between the two systems can be disrupted, and the body can get stuck in a sympathetically dominant state, with a low HRV. this can result in various mental and physical health problems. 




the factors that influence HRV are:

physiological factors. age, gender, genetic factors, and circadian rhythm, breathing mechanics and movement, influences in body position

lifestyle factors. diet, physical activity, stress, alcohol consumption, tobacco use, sleep, medications, emotion-cognition interactions, psycho-social stress etc.

diseases: diabetes, heart, lung and renal diseases, mental (anxiety, panic attacks) and neurological disorders (epilepsy) and other psychiatric diseases

external factors. climate (hot or cold environment), exposure to noise, and induced pain

contextual factors: recording method, sampling frequency, recording period length. artefacts,

influencing HRV

by carefully examination of these factors we can get the insight into the answer how to improve our HRV values. if your HRV is low, you can take steps to improve your HRV through lifestyle habits such as regular exercise, stress management, adequate sleep, and healthy eating.




MEASURING YOUR HRV

the variances in your heart rate are very small, so it takes specialized equipment or devices to detect them. modern technology has reached a point where non-medical devices that can track heart rate variability are affordable and liable for individual. in a medical setting, an electrocardiogram machine (EKG) is usually used to detect heart rate variability and is highly accurate. you could also use at home monitors that track your HRV continuously for longer periods of time (up to 24 hours). longer monitoring times tend to give the best data. outside of a medical setting, there are several devices commonly used: a device attached to a band that wraps around your chest, wrist-worn fitness devices and trackers and devices that attaches to a finger which are more sensitive and accurate.

i will state a few wearables although I have no personal interest behind nor is the order listed alluding to anything. Polar Beat Heart Rate Monitor, Garmin Heart Rate Monitor, AIO Smart Sleeve, OURA, WHOOP, Apple WATCH, Suunto Heart Rate Sensor, etc.




HRV VALUES

the evaluation of individual HRV values against reference values is limited because:
HRV IS HIGHLY INDIVIDUALIZED. what is a great HRV value it varies for everyone. it fluctuates greatly from one person to another as well as throughout the day, from one day to the next. HEART RATE VARIABILITY TRENDS ARE WHAT MATTERS. rather than comparing your heart rate variability to others, a more practical use of HRV is to follow your own long-term trends. to goal should be to see a gradual increase in your average heart rate variability. downward trend in HRV can be a sign that you are engaging in unhealthy behaviors, like overtraining, poor nutrition or insufficient sleep.

apple watch personal data DAILY

apple watch personal data MONTHLY

in general population the values for HRV are higher for younger people, males and athletes.

whoop.com

how to manipulate AND interpret the data from HRV to your advantage:

  • modifying the intensity and duration of your physical activity based on your heart rate variability will allow - you to train smarter and more efficiently - if your HRV is low it is a sign to cut back.

  • if you’d like to see the effect a new diet has on your body, the impact will be noticeable in your HRV

  • if your daily routine is unchanged but your HRV drops, it may be an indicator of increassed stress or oncoming illness

  • getting to know your sleep quality: in general during sleep your HRV should be higher, as it indicates the deep sleeping phase (during non-rapid eye movement stage (NREM) of sleep, parasympathetic cardiac innervation is more active, so it is predominantly only during REM stages of sleep when your cardiovascular system is steeply affected by sympathetic system and your HRV is higher). low sleep HRV may indicate sleep disorders, so if yours is consistently low, consider the factors that may affect it: stress levels, bedtime routine, sleep environment.



  1. Iwona Cygankiewicz, Wojciech Zareba. Handbook of Clinical Neurology, Volume 117, 2013, Pages 379-393, Chapter 31 - Heart rate variability

  2. Cygankiewicz I, Zareba W. Heart rate variability. Handb Clin Neurol. 2013;117:379-93. doi: 10.1016/B978-0-444-53491-0.00031-6. Review.

  3. Catai AM, Pastre CM, Godoy MF, Silva ED, Takahashi ACM, Vanderlei LCM. Heart rate variability: are you using it properly? Standardisation checklist of procedures. Braz J Phys Ther. 2020 Mar-Apr;24(2):91-102. doi: 10.1016/j.bjpt.2019.02.006. Epub 2019 Feb 26. Review.

  4. https://adamvirgile.com/2018/06/03/heart-rate-variability-hrv-in-sport-a-review-of-the-research/

  5. Stefan Sammito, Thielmann Reingard, Seibt Reingard, Irina Böckelmann. Guideline for the application of heart rate and heart rate variability in occupational medicine and occupational science. June 2015 ASU International 2015(06)

  6. https://www.whoop.com/thelocker/what-is-a-good-hrv/

  7. Amirreza Sajjadieh, Ali Shahsavari, Ali Safaei, Thomas Penzel, Christoph Schoebel, Ingo Fietze, Nafiseh Mozafarian, Babak Amra, Roya Kelishadi. The Association of Sleep Duration and Quality with Heart Rate Variability and Blood Pressure. 2020 Nov; 19(2): 135–143.

  8. Fred Shaffer, Rollin McCraty, Christopher L Zerr. A healthy heart is not a metronome: an integrative review of the heart's anatomy and heart rate variability. Front Psychol. 2014 Sep 30;5:1040. doi: 10.3389/fpsyg.2014.01040.

     

Sasa ObermajerComment