Measuring Heart Rate Variability at Home Is Easier Than You Think
We know why heart rate variability is so important and what to do to improve it, but how do we track our progress? The answer lies in commercial HRV monitors.
The Science Behind HRV Monitors
In a clinical setting, heart rate variability is measured by an electrocardiogram (ECG)¹. It involves placing electrodes on your chest to record the electrical signal of your heart, which is then translated into a readable graph. Doctors and clinicians can analyze the information and give us an understanding of our heart health. Of all the different methods used for analyzing cardiovascular data, an ECG is one of the most accurate and least invasive techniques.
However, for our purposes, it’s not the most user-friendly. Luckily, advancements in technology have given us the luxury of picking from a variety of different at-home, beginner-friendly HRV monitors. Most commercial HRV monitors are worn as chest straps or wrist/finger devices that use either photoplethysmography or electrocardiography to measure HRV².
- Photoplethysmography, or PPG, is a technology that detects changes in blood volume at the surface of the skin³. This technique uses LED lights and detectors that can sense changes in blood volume when the light is reflected or transmitted in different ways by human tissue⁴. PPG is most commonly used in devices that measure HRV through the finger or wrist.
- Electrocardiography, or ECG, is the same technology that is used in a professional, clinical setting⁵. However, when it’s converted to be used as an at-home HRV monitor, the multiple electrodes are replaced with a single, larger sensor that is meant to be worn against your chest.
Typically, an ECG device will give a more accurate reading compared to a PPG device. Research has shown that PPG devices tend to result in less accurate readings as the exercise intensity increases⁶, which can be a downfall if your goal for wearing a monitor is to track your HRV during and after exercise.
A Review of Some of the Top HRV Monitors on the Market
CorSense
Price: $165
CorSense uses the PPG technique to measure HRV from your finger. The device will read your finger and send the data via Bluetooth to an app on your phone. The compatible app, Elite HRV, comes with bio-feedback training and guided breathing techniques to help you improve your HRV. The device has a battery life of about 4 hours and takes between one to two hours to fully charge. Reviewers have praised the product for its simplicity and convenience; however, one of its major drawbacks is that it cannot be worn during exercise or sleep.
Price: $65
Zephyr HRM BT operates as a chest strap heart rate monitor that is wearable during exercise. The strap of the device is removable and washable, and the device itself is sweatproof and waterproof for immersion up to one meter of water. It has a remarkable battery life of over 26 hours, reaching full charge after 3 hours. The device connects via Bluetooth to a downloadable app that will give you data and analyses about your workout and recovery. However, reviewers have said that there are often difficulties with connecting to the device via Bluetooth, and some have reported inaccuracies in the readings made by the device.
Price: $90
Polar H10 is also a wearable chest strap device that uses ECG technology. The device connects via Bluetooth to the company’s own app, Polar Beat, and can also connect with the company’s fitness watch to give even more information about your workout. The Polar H10 is meant to be worn during exercise and it is fully water-resistant. The device is non-rechargeable and uses a single CR-2025 battery that will last for over 400 hours.
Price: $169 to $499 (depending on the type of garment you purchase)
Hexoskin Smart Garments is one of the only monitors in the form of clothing. The garments use special textile sensors that monitor cardiac, respiratory, sleep, and exercise data through ECG. These garments include machine-washable tank tops and T-shirts designed for men, women, and children. The material is breathable, lightweight, and provides UV and chlorine protection. The garments can connect via Bluetooth to your phone and can be plugged into your computer via a USB charging cable. The device is 12–30 hours of battery life on a single charge.
Price: $18 to $30 per month
Whoop is unique in that it is a membership-based program that uses a PPG device to monitor your sleep, exercise, and recovery indexes. The device is wearable on your wrist or upper arm, and it connects to the Whoop app. The membership fee allows you to use the app and benefit from the coaching and personally-curated exercises developed based on your unique readings. The device has a battery life of 5 days and has a portable charger that can charge the device while it’s in use. The plan comes with a 6-month commitment when you first purchase it, and you get the device for free. You can purchase accessories and different bands to use with the device.
Apple Watch
The Apple Watch is also a great way to monitor your HRV. The function is available on any watch operating watchOS 4 and iOS 11 and beyond. The device automatically reads your HRV when you first put on the watch in the morning, but you can also choose to manually start a reading anytime during the day with the Breathe app. It automatically measures your HRV while you are doing your 1-minute breathing. Each reading lasts for one minute and the program will calculate your HRV average in milliseconds.
To view your HRV stats, check the Health app and you’ll be able to see your readings for the past day, week, month, and year. The Apple Watch uses PPG to conduct its readings, so it will have the same downfalls of being less effective during intense exercise, but it is a great way to incorporate HRV awareness into your health routine.
How to Pick the Right Monitor for You?
We’ve just talked about several different HRV monitors that all come with different perks, but how do you pick the right one for you? It’s important to consider how you want to use your device. Are you looking for something to wear while you exercise to track the way you train and help you improve? If so, you might want to look into a wearable ECG chest strap that will track your signs during and after exercise. If you’re looking for something to monitor your HRV throughout the day and improve your stress levels on a day-to-day basis, then a PPG finger monitor might be better fitted for you. Consider your lifestyle and daily activities and what you want to gain from monitoring your HRV before making the decision to purchase any HRV device.
Endnotes
- Peake, Jonathan M., Kerr, G., Sullivan, J. P. (2018). A Critical Review of Consumer Wearables, Mobile Applications, and Equipment for Providing Biofeedback, Monitoring Stress, and Sleep in Physically Active Populations. Frontiers: Physiology. doi.org/10.3389/fphys.2018.00743.
- Georgiou, K., Larentzakis, A. V., Khamis, N. N., Alsuhaibani, G. I., Alaska, Y. A., & Giallafos, E. J. (2018). Can Wearable Devices Accurately Measure Heart Rate Variability? A Systematic Review. Folia Medica, 60(1), 7–20. doi.org/10.2478/folmed-2018–0012.
- Ibid.
- Ibid.
- Ibid.
- Ibid.
