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Are Heart Rate Monitoring Apps Really Accurate? We Put Them To The Test

Health has become the focus of many new gadgets with personal fitness bands growing increasingly popular. Health apps have become a stock feature in both Android and iOS and long before that happened, developers had been working to put the these devices to better use. There have long existed apps that claim to measure your heart rate using nothing more than the front and/or rear camera on your phone. People obviously have their doubts about apps like this because measuring medical information can’t be that simple. I’ve personally tried to ‘fool’ these apps and those that claim to measure heartbeat by scanning one’s face are quite easy to fool with nothing more than a picture placed in front of it. We did however decide to give these apps a chance; see if they really can measure a person’s heart rate and how accurate the reading is.


The experiment involved three apps; Cardio, Heartrate by Runtastic, and Heartrate by Azumio. All three apps are incredibly popular, and have been prominently featured in the App Store, and are well endorsed. They were up against two contenders; the first was my index finger. The heart rate is nothing more than your pulse and you can count how many beats you have by placing two fingers over your radial artery. It’s so easy, many of us learned to do it in school. The second contender was a digital heart monitor. It’s a medical apparatus that uses a proper pressure cuff to measure your blood pressure as well as your pulse.

As far as accuracy is concerned, the manual two-finger over the radial artery was taken as the most accurate. It was cross referenced with the average resting heart rate of an adult which is 72bpm (beats per minutes). The tests measure accuracy, the number of attempts needed to make a correct measurements, and how long it took to get a reading. The test subject was measured in a state of rest, does not suffer from hypertension etc, and is not underweight or obese.

Manual Pulse recorded: 79bpm

Digital Heart Rate Monitor

Reading: 76bpm

Accuracy: Highly accurate

Time taken: 30 seconds

Attempts: single attempt


The Apps


Reading: 74bpm

Accuracy: Highly accurate

Time taken: 15 seconds per attempt

Attempts: eight attempts

Cardio Cardio_save

Cardio was a disappointment in terms of how many times I had to make a measurement. It constantly gave readings as low as 42 or 56. It seems that the slightest movement, something as simple as taking a deep breath may put the app’s counter off the mark. It’s disappointing because when you go to the doctor’s for a check-up or if you were even to use a digital heart rate monitor like the one pictured above, you would be instructed to breath normally. That said, when the app finally gave a decent reading, it was accurate. Cardiio can connect and share date with the Health app on iOS 8.

Download Cardiio From The App Store

Heartrate by Runtastic

Reading: 78bpm

Accuracy: Highly accurate

Time taken: 10-12 seconds

Attempts: single attempt

heartrate_runtastic runtastic_reading

Heartrate by Runtastic is pretty good at accounting for normal body movement. So long as the subject’s finger remains in contact with the camera lens, it will continue to measure the heart rate. If the subject is moving too much, it will prompt you to stay still indicating that the reading might be inaccurate. That doesn’t mean it can’t give an inaccurate reading but an inaccurate reading is more the result of movement like shifting in your chair and not simply taking a deep breath.

Install Heartrate by Runtastic From The App Store

Install Heartrate by Runtastic From The Google Play Store

Heartrate by Azumio

Reading: 72bpm

Accuracy: Highly accurate

Time taken: 15 seconds

Attempts: single attempt

heartrate_azuio heartrate_azuio_reading

This app had the fewest failed measurement attempts. If it detected a problem, it would simply start over. It can share data with the Health app in iOS 8 and I actually found it worked better than Cardiio. The app has a premium version as well and it comes with more features.

Install Heartrate by Azumio From The App Store

Install Heartrate by Azumio From The Google Play Store

The Verdict

These heart rate monitors are indeed accurate. Getting the correct reading might take a few attempts but the reading isn’t wrong or that far off the mark. That’s not to say they will be replacing your GP but for anyone exercising, or wanting to monitor their vitals without purchasing an add-on for their phone, these apps are pretty useful.

A note about accuracy: GP’s normally instruct adding or subtracting ten from the reading of a digital device depending on the trend (if your reading is normally higher than average, add ten, if it is less than average, minus ten). The number ten represents the acceptable range of deviation and was used to determine accuracy.

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