Heart rate measurements have been part of our medical routines for quite some time. It is only relatively recently that heart rate monitors have become available for personal use. Essentially, a heart rate monitor is a portable device that is used to measure how fast your heart beats. Some devices can only measure and display your heart rate real time, while other devices also store this information for future use or study. Most contemporary devices and gadgets use heart rate sensors to measure your heart rate, and use that data to understand your performance while exercising or performing other kinds of physical activities. Here we are almost exclusively interested in the heart rate monitors in the commercial sector, which are designed as part of other devices and gadgets, such as baby monitors, sport swatches, fitness trackers and similar.
The purpose of a heart rate monitor in fact starts with the sporting industry, despite being used by medical professionals almost exclusively. Nevertheless, portable devices have existed since the early 1980s and were used by professional athletes to measure heart rates during intense workout sessions. Today, heart rate monitors are used by a quickly growing number of consumers, primarily because of rapid technological advances that allow for smaller sensors that fit in fitness trackers and smart / sport watches.
Methods and technology
There are currently two methods of recording heart rates in contemporary commercial devices: electrical and optical signals. Both of these can be highly reliable and the quality does not necessarily depend on the method or technology used. Instead, it is the underlying algorithm and the quality of the sensors themselves by which the accuracy of the heart rate measurements is determined. The algorithms are based on Pan-Tompkins and are more often than not proprietary to the company or brand selling the devices.
Corresponding to commercial uses, the medical professionals use two other kinds of methods: electrocardiography (ECG) sensors measure how quickly the heart chambers contract or expand; and photoplethysmography (PPG) sensors use light to measure how much blood moves through the veins. Let us focus on these for a quick explanation on how they work:
Electrical signals have been in use for quite some time and are in essence based on the first heart rate monitors. They consist of two parts: a transmitter that is worn around the chest (close to your heart) and a receiver that interprets the transmissions. With every heartbeat, a signal (usually a radio signal, but also Bluetooth, ANT, ANT+, etc.) is sent to the receiver part, which then determines and depending on the model also displays what the current heart rate is.
Optical signals are relatively new on the market and are similar to PPG used in the medical field. In such devices the receiver and transmitter parts are usually within the same device (such as a watch). Similar to photoplethysmography sensors, the measurement takes place by shining a bright light and looking at how much blood volume passes through and how blood vessels are scattered off. One great advantage of this technology is that it can be used to measure more than just heart rates, but also for example the levels of oxygen saturation.
Due to their size, optical signals (and PPG) are used most frequently in consumer devices such as watches and fitness trackers. Coupled with other sensors, many smartwatches and fitness trackers are able to monitor your heart rate, oxygen saturation, your speed, distance and location through GPS, and so on.
Popular brands for heart rate monitors
For the purpose of fitness and sports, consumer heart rate monitor brands include Garmin, Fitbit, Apple and Samsung. The earliest heart rate monitor was developed by Polar Electro, which still makes heart rate monitors, ranging from sport belts to sport watches and perhaps the best looking waterproof watch we have seen. We have recently written a review of Men’s Polar FT60 watch and Women’s Polar FT60 watch, as well as a Polar Sports Bra with a heart rate monitor.
Another big player on the market for heart rate monitors is Suunto that also has a variety of products on the market. Occupying the higher end of the market, it offers the most comprehensive sport watches with features and functions to track a complete workout.
With the popularity of these products, a lot of new brands have entered the consumer market and offer relatively low-priced alternatives to the big brands. If you are on a budget consider a YAMAY smartwatch or a Xiaomi Huami Amazfit Bip. We have written a review for both these smart watches as well – YAMAY review and Xiaomi review can be found by following the links.
Fitbit Versa 2 Health & Fitness
Garmin Vivoactive 3
Apple Watch Series 4
Samsung Galaxy Smartwatch
Polar Ignite – Advanced
Suunto 9 GPS
Xiaomi Huami Amazfit Bip
All links are to Amazon.