Smartwatches are great, not just for providing notifications without making us have to pull out our smartphones to check them, but also for our health. The Apple Watch, for example, will prompt you to get up and walk around at regular intervals, as well as alerting wearers if they have an irregular heart rhythm they should get checked out by a doctor.

But not everything about fitness-tracking smartwatches is so good for our health, claims a new report from the University of Copenhagen in Denmark. It suggests that smartwatches, while providing no shortage of useful data, also increase anxiety levels. In a study of 27 heart patients who use Fitbit trackers to measure their sleep, heart rates and physical activity, the researchers found that the more people learned about their biometric data, the more anxious they became about it.

“Our study shows that, overall, self-measurements are more problematic than beneficial when it comes to the patient experience,” Tariq Osman Andersen, an assistant professor at the University of Copenhagen’s Department of Computer Science, said in a statement. “Patients begin to use the information from their Fitbits just as they would use a doctor. However, they don’t get help interpreting their watch data. This makes them unnecessarily anxious, or they may learn something that is far from reality.”

The insight is interesting, albeit just another example of the kind of tech creep we’ve seen as other pieces of technology, purporting to make our lives easier, have become more and more ubiquitous. A smartphone that allows you to make calls whenever you want also allows you to be called whenever. Social media that connects people also makes it possible to bully people. As cultural theorist Paul Virilio once pointed out, the inventor of the ship is also the inventor of the shipwreck.

In keeping with that dichotomy, Osman Andersen said that, in situations where the Fitbit data showed people that why were sleeping well and had a normal heart rate, it could be calming. It was when the results weren’t so good that they tended to be detrimental to people’s anxiety.

Hopefully more studies will be carried out to explore this phenomenon in more detail, and using other smart wearables, in the future. From the sound of things, device makers should also do more to ensure that users are able to properly interpret the data they are shown.