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Wellness

How to track your heart rate with only your smartphone

You don't need a heart rate monitor or smartwatch to take your pulse -- these three apps can do it with your phone.

iphone7mockup-cardiio4-1280-811

The Cardiio app helps you understand how your heart rate is related to your health with features like "Fitness Level" and "Endurance Score."

Cardiio

Tracking your heart rate can be a great way to monitor your heart health, and thanks to smartphones, it's never been easier. A variety of apps can leverage your phone's camera to measure your heart rate without any kind of heart rate strap or other accessory.

Here's how they work and three apps worth trying.

Read more: Heart-rate tracking is the secret to getting fit. Here's how to use it | What should your resting heart rate be?

How these apps can track your heart rate

Similarly to the heart rate trackers built into most fitness wearables, apps on your phone can measure your heart rate by detecting changes in blood volume below the skin's surface -- a practice called photoplethysmography

Here's how it works: Every time your heart beats, the amount of blood that reaches the capillaries in your fingers and face swells and then recedes. Because blood absorbs light, apps are able to capture this ebb and flow by using the flash of your phone's camera to illuminate the skin and create a reflection. 

How accurate are these heart-rate tracking apps?

Although photoplethysmography is a tried-and-true practice, not all heart rate tracking apps are created equal. When researchers compared four of them to clinical gold standard measurements (ECG and fingertip pulse oximetry), they found that the heart rate readings generated by apps were off by more than 20 beats per minute in over 20% of measurements. 

The fact that heart rate apps don't consistently perform as well as clinical-grade equipment isn't too surprising -- most, if not all, warn against medical use -- but even within the apps, there were some winners and losers. 

According to the study, apps that ask you to touch your finger to your phone's built-in camera tend to be more accurate than those that just ask you to hold your phone's camera up to your face. 

Bottom line: App readings should always be taken with a grain of salt, but if you're just looking for a high-level overview of your heart rate over time, it's hard to beat the convenience of smartphone apps. With that in mind, below are three finger-touch heart rate apps that consistently come out on top. 

Cardiio: Heart Rate Monitor

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Screenshots of the Cardiio iOS app.

Cardiio, Inc.

Based on technology licensed from the Massachusetts Institute of Technology, Cardiio measures your heart rate in under 15 seconds flat. If you need a reminder to take your pulse, activate the built-in alert and set it to daily, weekly or monthly. 

Take advantage of the free circuit workout to get fit and improve your stats, then easily export your data to wow your doc. Cardiio is completely free to use -- you don't even have to create an account. To unlock additional features, pay for them piecemeal (starting at $4.99) or upgrade to pro for a one-time payment of $9.99. The app also syncs with Apple Health

Price: Free for iOS with in-app purchases

Instant Heart Rate: HR Monitor

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Screenshots of the Instant Heart Rate Android app.

Azumio Inc.

This app is a favorite of heart rate researchers (it was even used in the study mentioned above). Like Cardiio, this heart rate monitor is free to use, but nearly everything else is behind a subscription paywall ($9.99 a month or $59.55 a year). 

It's not cheap, but what you get access to is pretty substantial: goal-based health programs like "Lose Weight" and "Get Active," a food log, healthy recipes, step challenges, manual sleep tracking, and more. Syncs with Apple Health and Google Fit.

Price: Free for iOS and Android with in-app purchases; $1.99 for Windows

Cardiograph

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Screenshots of the Cardiograph iOS app.

MacroPinch Ltd.

With Cardiograph, you can measure your pulse while you're at rest or in motion. You can tell the app what you are doing while you're taking your pulse (resting, walking, running, etc.) so that the numbers are stored with added context in your health history. The app syncs with Apple Health and Android Wear—there's even version native to the Apple Watch ( $439 at Walmart)

If you're using the Android version on a shared device, you can set up multiple profiles for family and friends. On iOS, you can text your heart rate to a loved one using the app's iMessage extension. The old version of this app -- Cardiograph Classic -- is still available for 99 cents, but the clean, intuitive design of the new version makes it well worth the extra buck. 

Price: Free for Android with in-app purchases; $1.99 for iOS

The information contained in this article is for educational and informational purposes only and is not intended as health or medical advice. Always consult a physician or other qualified health provider regarding any questions you may have about a medical condition or health objectives.