The authors of a new study published in the European Journal of Preventive Cardiology are warning about the accuracy of iPhone heart rate apps.
“Heart rate apps come installed on many smartphones and once people see them it is human nature to use them and compare their results with others,” said senior author Dr Christophe Wyss from Heart Clinic Zurich, Switzerland. “The problem is that there is no law requiring validation of these apps and therefore no way for consumers to know if the results are accurate.”
The study tested the accuracy of four commercially-available apps against ECG and fingertip pulse oximetry. Accuracy varied dramatically between the apps. Non-contact apps performed less well than contact apps, particularly at higher heart rates and lower body temperatures. Non-contact apps had a tendency to overestimate higher heart rates. One app measured heart rate with comparable accuracy to pulse oximetry.
“Consumers and interpreting physicians need to be aware that the differences between apps are huge and there are no criteria to assess them. We also don’t know what happens to the heart rate data and whether it is stored somewhere, which could be an issue for data protection,” Dr Wyss concluded.