In this era of 24/7 connectivity, our lives have become overly dependent on our phones. Beginning with simple calls and texts, leading to entertainment, the IoT has brought a time where we even let our health depend on our smartphones without giving a second thought. Fitness apps have become popular over the past couple of years. A study at the University Hospital of Zurich has demonstrated that heart rate apps do not take accurate measurements and it is rather scary how we depend on them for our lives.
The author of the study Dr. Christophe Wyss is a cardiologist at Heart Clinic Zurich who says it is “human nature” wanting to try out the apps, even when you feel healthy. “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.” he said.
Some heart rate apps take measurements using contact photoplethysmography by touching the fingertip to phone’s camera or by non-contact photoplethysmography that only asks you to hold the camera in front of your face. The technique illuminates the skin and measures the changes in how much light is absorbed as the blood is pumped in the body.
The study was published in the European Journal of Preventive Cardiology. It tested four commercially available popular heart rate apps on more than 100 patients. Two of these used the contact technique while the other two were noncontact. Simultaneously, Electrocardiography (ECG) was performed on the same patients, which is considered the gold standard for heart rate measurements, along with fingertip pulse oximetry which is based on photoplethysmography.
The results of the study showed that the measurements from ECG and the apps had a difference of up to 20 beats a minute. The performance of the contact apps was found to be much better than that of the noncontact apps, which overestimated the heart rate for the most part.
The contact apps showed a surprising difference in reading from each other despite the fact that they were based on the same technology. The researchers concluded that the difference could depend on camera technology, age, and even body temperature. Dr. Wyss said:
“The one contact app was excellent, performing almost like a medically approved pulse oximeter device. But the other app was not accurate, even though they use the same technology. 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 accurate. 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.”
Fitness and heath apps are widely popular, but they have not proven to have any positive benefits. And this is not limited to physical health applications, a 2016 study from the University of Pittsburgh showed that NHS-endorsed mental health apps are ineffective and even the fitness apps may not help the users lose any weight.