How Can Heart Rate Variability (HRV) Leverage Digital Health?

Health is wealth and knowledge is power, they say. These days, it seems like everyone is talking about a relatively new and potentially revolutionizing health tracking unit called Heart Rate Variability (HRV). We believe there is a good reason for this, and today we are here to help you understand the benefits of HRV tracking, how it is connected to the nervous system, and how monitoring it can improve stress management and help your body perform at full capacity.

Thanks to its ability to provide insights into how different behaviors affect the nervous system, heart rate variability has the potential of becoming a preventive tool and assist the healthcare system in the effort to reduce the ever-rising numbers of patients suffering from cardiovascular diseases. It is also a valuable tool in understanding how the nervous system influences performance, endurance and adaptability of the body.

At KENKOU, we believe uniting medical knowledge with technological innovation can help people take charge of their own health in an easy, affordable, and sustainable way, so we combined medical and health tech expertise to deliver a product that brings cardiovascular health insights closer to those who need it the most – actual patients.

What is HRV and why is measuring it important?

“HRV represents a non-invasive, pain free, economic and simple measurement.”

Sylvain Laborde, German Sport University Cologne

Short for Heart Rate Variability, HRV is a measuring unit of the variability between heart beats. It represents changes in the time interval between successive heartbeats. A healthy heartbeat is no metronome – it beats at varying intervals, and the distance between these beats can tell you a lot about the state of your nervous system, your body’s adaptability to various situations, its readiness to cope with stress, and how quickly it can recover.

Many people misinterpret the BPM (beats per minute) rate, assuming that a heart rate of 60 BPM means that the heart beats once every second. In reality, the distance between two consecutive heartbeats (also known as the RR interval) might be 0.95 seconds, while the following two might beat with 1.05 seconds between them. HRV tracks the changes in time between successive heart beats to demonstrate how well the nervous system is responding to various factors that affect it.

heart rate and heart rate variability chart

What affects HRV and why does it matter?

One of the main roles of the nervous system is helping the body handle everyday life challenges in the best way possible. The so-called autonomic nervous system (ANS) regulates many vital functions of our organism, like breathing, sweating, or maintaining the correct body posture. Most of these functions, including heart activity, are regulated without our consciousness.  

ANS sends signals to our heart through its two branches – sympathetic and parasympathetic. These two ANS branches are constantly active but in varying intensities, depending on the nature of the situation the body is faced with. When dealing with stress (like performing work on a tight deadline), the sympathetic branch activates stress hormones, putting the body in “fight or flight” mode. In contrast to that, the parasympathetic branch activates during more relaxed and less stressful times, placing the body in “rest and digest” mode.

ANS is constantly working and regulating functions that might appear to be automatic, like breathing, digestion, and, of course, the heart rhythm. As an independent unit, the heart rate on its own beats to a rhythm that is dictated by the sinoatrial (SA) node, which acts as a built-in pacemaker, maintaining the heart rate at around 100 beats per minute. However, the balance between the sympathetic and parasympathetic branches of ANS changes its rhythm throughout the day, either allowing one branch to dominate or by keeping them in balance. The constantly changing configuration of the influence ANS has on the heart rhythm ensures a flexible adaptation of the cardiovascular system to internal and external demands on the body.   

What this means is that any one of the two branches of ANS can be dominating at any given time, or they can remain in perfect balance. If the sympathetic branch is dominating (like when we are facing a stressful situation), the heart rate goes up and the heart rhythm becomes uniform, which causes the HRV to go down. On the other hand, if the parasympathetic branch is dominating (like when we are relaxed and comfortable), the heart rate goes down and the beats are more spread apart, causing the HRV to go up. In general, a higher HRV is an index of a well balanced regulation of cardiovascular functioning. 

What is a good HRV measurement and how does it affect overall health?

A high HRV is a sign of a well functioning parasympathetic system, which extends the adaptability of cardiovascular responses to various challenges. This is why a high HRV is usually considered to be a good sign. However, as we will see through many examples, a high or low HRV alone does not always indicate optimal performance capacity (or the opposite).

A low HRV rate usually means that the sympathetic branch of the ANS is dominating and the body needs to be ready to take on more stress than normally, making it beat faster and lowering HRV. This is not necessarily bad. For example, when the body is physically exerted (like during an intense workout), the nervous system sends signals to the heart that its focus should be on managing the exertion, rather than focusing on internal processes like digestion or recovery. 

The low HRV in this case simply indicates the efficiency of the nervous system to prioritize certain functions inside the body. This explains why observing HRV alone without taking into consideration other factors that could be affecting it is insufficient and can result in inaccurate and misleading conclusions. 

The recovery ability of your cardiovascular system is measured through the root mean square of successive differences between normal heartbeats (RMSSD). The higher the variability value, the more capable your heart is to cope with challenges and recover from them. As recovery ability values vary depending on the age, gender and other factors, the following table shows average RMSSD for healthy men and women of different ages.  

How is HRV measured and what equipment does it require?

Thanks to advanced technology and widespread use of smartphones, measuring heart rate variability represents an affordable, easily accessible and non-invasive method for monitoring health. However, analyzing and interpreting the collected data is a far more complicated process. When it comes to HRV, each patient has to be observed as an individual with a unique body structure and their own specific way of processing and reacting to factors that affect the nervous system.

This is why, when it comes to result interpretation guidelines, there is no “one size fits all”, which is only one of many reasons HRV data can be difficult to interpret. The good news is that, over time and with experience, it becomes much easier to read and understand the collected data. 

anatomical heart and heart rate chart

What are the benefits of measuring HRV?

Tracking heart rate variability and interpreting its units has the potential of creating a new niche in the health tech industry. It requires no medical hardware or additional healthcare costs and eliminates the need for constant doctor’s supervision, while its convenience and ease of use have the potential of bringing health monitoring closer to patients. In addition to that, understanding how HRV is linked to health affecting habits like smoking and drinking, or sleep quality and diet, can help millions of people take better care of their health and help them develop sustainable and long-term healthy habits.

By enabling patients to measure the scientific biomarker HRV themselves, general awareness around health and the importance of preventative care is raised. Measuring HRV regularly helps people not only understand their nervous systems and how it regulates the heart rhythm,  but also teaches them how they can improve overall performance, manage stress better, and live longer and happier lives.

HRV data-interpreting tools therefore have an immense potential in leveraging digital health, as they provide metrics which provide insights about the health of the nervous system, stress reactions, and consequently the entire body. HRV is able to monitor digital therapies (and their effectiveness) over time, which is urgently needed in health tech. 

Additionally, measuring HRV is a necessary first step towards improving it.  A scientifically proven way to improve HRV are biofeedback exercises. Common HRV biofeedback exercises leverage the physiological connection between the breath and the heart and provide individuals with real-time feedback on their current HRV while performing a breathing exercise.

In conclusion, HRV measuring tools enhance the value of countless health related apps, whether they focus on fitness and performance, pregnancy tracking, heart health or other vital information that can help people understand and improve their overall health.