Learn About Heart Rate Monitors

A heart rate monitor senses and displays your heart rate. Walkers can use their heart rate to adjust the intensity of their walk, speeding up or slowing down to stay in their chosen heart rate zone. Two walkers going the same speed may be in different zones—one barely working at all, the other near maximum and straining. As your fitness improves, you can walk faster at the same heart rate.

The most accurate heart rate monitors use a chest strap which fits snugly around your chest just below the breast. The transmitter detects the electrical activity of your heart just like an ECG. It relays this to a display, usually worn like a wristwatch, or transmits it to cell phone apps via Bluetooth. It is important for the strap to maintain contact with the skin on your chest or you will get wild readings.

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These devices are worn as a wristwatch or armband and use optical sensors on the back of the device to continuously read your pulse through the skin. You get a real-time readout of your heart rate, just as with the chest strap monitors. However, there are limitations.

Those using infrared get interference from muscles, while those that use only green light (such as the Apple Watch) may not be able to get readings through tattoos or dark-pigmented skin. Some, such as the Scosche Rhythm+, use a yellow light sensor as well to overcome that problem, according to Dr. Steven LeBoeuf of Valencell.

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These monitors work by detecting your pulse, usually by placing one or two fingers on sensor buttons. They cannot give you a constant reading of your heart rate, you have to take it on demand instead. They are also trickier to use than the chest strap monitors. Cold fingers, for example, can give you no reading or wild readings.

Basic models display only your heart rate, and perhaps elapsed exercise time. With increasing price, you get a variety of useful features such as:

• Heart rate zone alarm: Set the zone and it alerts you when you are high or low
• Timers: Countdown timer, stopwatch, interval timers, clock, alarm
• Calories burned
• Time in zone splits
• Fitness test
• Computer/app link
• Pre-programmed workouts

Besides features, shop for how easy a heart rate monitor is to use. Can you read the numbers easily? Does it have a backlight for use in low light? Are there so many features that you will have to carry the manual to figure out how to use it each time? Are the buttons well labeled and easy to find and push?

If you use a chest strap that has no monitor other than the cell phone app, how easy is it to use? Does it give you regular audio updates or do you have to check the screen? Can you use a variety of apps with the chest strap?

Once you have chosen which features you want, it comes down to price. Sales are common and you can find a wide variation in the price of the same model. Shop around and you may be pleased to find your dream monitor for much less than suggested retail price.