Digital Technology, Health Apps, Heart Diseases, Heart Health, Heart Monitoring, Holter ECG

How Do Heart Monitors Work? Value of HRV and EKG Data

How Does a Heart Monitor Work

Heart monitoring is vital for persons with cardiovascular disease and useful for those at a higher risk of developing them.

Insight into the function of our heart helps us adjust lifestyle accordingly.

Many people monitor heart function to modify their workouts. But this post is not about fitness trackers that show your heart’s activity, really.

Throughout this post, we are going to discuss how does a heart monitor works and shed light on ECG and HRV.

What is ECG?

Electrocardiogram (ECG, EKG) is a test that analyzes the rhythm and electrical activity of the heart. As a common and painless test, ECG helps diagnose arrhythmias, whether a patient has had a previous heart attack, coronary heart disease, or cardiomyopathy. Also, ECG can show whether treatments for heart disease are working properly.

What is HRV?

Heart rate variability (HRV) is a measure of variation in time between each heartbeat. The autonomic nervous system (ANS) controls this variation, and it has two branches: parasympathetic (deactivating) and sympathetic (activating). The first branch deals with inputs from internal organs and causes a decrease in heart rate. The latter showcases response to exercise or stress, and it increases your heart rate.

HRV occurs when these branches send signals to the heart at the same time.

Keep in mind normal; the healthy heart doesn’t tick evenly. In milliseconds between heartbeats, variations are present constantly. We are not really aware of these variations because HRV is not the same as heart rate.

A person can get a sense of their HRV if they place fingers on the wrist to feel the pulse while deeply inhaling and exhaling. Between the beats, the interval gets longer, meaning heart rate slowed down as they breathe out. But when they breathe in, the interval gets shorter since their heart rate increases.

Factors such as metabolic processes, hormonal reactions, cognitive processes, exercise, recovery, and stress influence your HRV.

How Does a Heart Monitor Work

How does a heart monitor work

Regular ECG only records heart signals for a few seconds. The device is not portable. For that reason, you may need a Holter monitor or event monitor. You might wonder how it looks and how does a heart monitor work.

A Holter monitor is a portable ECG that records the heart’s electrical activity for 24 to 48 hours while you are performing regular daily activities.

The monitor features electrodes that are placed on the chest and stomach and then connected to wires. You can wear a monitor box over the shoulder or around the waist.

You can also find more advanced monitors like the ECG Holter patches, which you can easily put on your chest by yourself without any wires and monitor your heart health for up to 268 hours while continuing your daily activities even showering. Further, you can easily upload your data or send your patch to a professional who will do it in your place. Afterward, your data will be analyzed and you and your doctor will receive information about any detected abnormality.

An event monitor is also a portable device that records the electrical activity of the heart.

Unlike Holter monitor, this device doesn’t record continuously, only when you activate it.

Some event monitors automatically start reading upon detection of abnormal heart rhythm. Patients can wear event monitors for a month or even longer. We can divide these devices into symptom event monitors and memory looping monitors.

The doctor analyzes ECG results and recommends further tests if necessary.

An ECG picks up heart rate abnormalities. The normal heart rate is 60 to 100 beats per minute. Values that are higher or lower than this indicate the presence of an underlying problem.

The ECG data also shows where and how the heart is beating out of rhythm. At the same time, reading ECG data helps doctors determine how hard the heart is working in specific areas. Abnormal ECG could indicate one section of the heart is larger or thicker than others.

When it comes to HRV data, the standard for their analysis is to evaluate a long strip of ECG. So what does HRV value tell you? A lot of things, actually! As mentioned above, HRV is about detecting ANS irregularities.

Variation between subsequent heartbeats tends to be low when fight-or-flight mode is on. But if you are relaxed, variation between heartbeats is high. More precisely, you are more resilient and flexible when ANS is healthier. Low HRV values could be associated with anxiety and depression, a higher risk of cardiovascular disease, and death. It also means one branch is dominating, usually the sympathetic, and sends stronger signals to the heart than the other branch.

On the other hand, high HRV values indicate better cardiovascular fitness and show a person is more capable of resisting stress.

HRV is a sensitive and highly individualized metric. The values may fluctuate throughout the day and from one person to another.

Are Apps and Wearable Devices Reliable?

How does a heart monitor work and are they reliable

Nowadays, there are different monitors, devices, or apps that claim they can measure HRV or ECG accurately.

The accuracy of these devices may vary from one device to another, but they could be less effective than doctor-used monitors.

As technology evolves, we can expect these devices and apps to evolve as well and become more sensitive to detecting heart-related irregularities. If you plan to use a tech gadget that measures ECG and HRV, you may want to consult your doctor first and ask them about the accuracy of those devices.


Heart monitors mean the world to persons with heart problems and those who are at a higher risk of developing them, therefore it’s important to understand how does a heart monitor work and how it can help you. These devices show whether the heart is functioning normally or not, thus allowing the doctor to recommend the most suitable approach to prevent heart disease or avoid worsening it. The value of ECG and HRV data is immense, especially because the latter can also demonstrate a person’s resilience to psychological stress as well. While wearable tech is available today, accuracy is still not certain but could be improving with the evolution of technology in medicine.

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