Dr Andersen, who completed the study with researchers from Vital Beats, a Danish medtech company, added: “Conversely, the Fitbit watch can be calming, if data shows that you are sleeping well and have a low heart rate.
“The problem is that you cannot use data directly related to heart disease because the watch is designed for sports and wellness, as opposed to managing disease.”
The fitness-tracking watch also made many patients feel more guilty when they fell short of their daily fitness goals.
On the one hand, patients were motivated to be active, but the app also revealed when patients did not reach the recommended 10,000 daily steps, making many feel guilty.
Dr Andersen explained that the guilt was misplaced, and said: “The Fitbit watch is not designed for heart patients, so they should not necessarily follow the same recommendations for exercise as those who are in good health.”
The use of wearable health tech, such as the Fitbit watch, is part of a growing trend to measure activity in healthy people and those with chronic illnesses.
The research team said the fitness watches and their accompanying apps offer great promise for heart patients, helping to engage patients in managing their illness outside of the hospital.
But the team suggests they should now be used in partnership with healthcare professionals to limit unwanted side effects.
Dr Andersen added: “We believe it is time to think in terms of ‘collaborative care’, where both patient and clinicians benefit from the new health data and are thereby able to work together to manage and treat chronic diseases.
“This requires that we create a digital platform in which clinicians and patients can jointly interpret data from, for example, fitness watches, without creating unnecessary additional work for clinicians.”