Fitbit, Jawbone, Microsoft, Samsung and Xiaomi are just a few of the big names cashing in on the health and fitness tracking craze (heck, there’s even a fitness monitor for man’s best friend). While the data produced by such trackers can serve as motivation to get into shape and stay that way, some may be surprised to learn that the data will be of little value to your doctor.

In a recent article from MIT Technology Review, Andrew Trister, an oncologist with Sage Bionetworks, said he’s seen some patients that come in with large Excel spreadsheets full of fitness tracker data and that he has no idea what to do with it. Neil Sehgal, a senior research scientist at the UCSF Center for Digital Health Innovation, tends to agree. Sehgal said clinicians can’t do a lot with the number of steps you’ve taken in a day.

Worse yet, Sehgal and his colleagues have compared the data generated by consumer wearables against relevant clinical gold standards. In multiple studies over the past two years, they’ve determined that very few devices currently on the market are as reliable as data gathered from medical-grade devices.

That shouldn’t come as a huge surprise considering almost all health-related wearable devices aren’t regulated in the same way that true medical-grade devices are. While that may be disheartening for some to learn, it’s not a total wash as Sehgal concludes that such devices are useful because they help people become more active.