Heart rate app on your phone may not be accurate

A study has discovered a huge variability between commercially available programmes installed on the gadgets. Many readings are not correct
and pose a significant health threat to users if they believe the readings to be correct.

Dr Christophe Wyss, a cardiologist at the Heart Clinic Zurich, said: 'Heart rate apps come installed on many smartphones and people use them and compare their results with others.

'The problem is that there is no law requiring validation of these apps and therefore users do not know if the results are correct. 108 patients had
their heart rate measured using four apps on two different iPhone models.

Two clinical methods were used for comparison, including an ECG and fingertip pulse oximetry, which uses similar technology to that of the apps.
Half of the apps adopted allowing placing  of fingertip on the phone.

The researchers found substantial differences in accuracy between all of the four commercially available apps.
In some there were differences of more than 20 beats per minute compared to the ECG readings.

The researchers added that despite being relatively easy to use, the non-contact one performed the worst and had a tendency to report higher rates.
However, the performance of the two contact-apps was also different, with one providing similar results to pulse oximetry, while the other didn't.

Dr Wyss added: 'The difference in performance between the contact apps is probably down to the algorithm the app uses to calculate heart rate which is commercially confidential.

'It means that just because the underlying technology works in one app doesn’t mean it works in another one and we can’t assume that all contact heart rate apps are correct.