From steps and calories to heartbeats, your smartwatch tracks it all.

Studies show people who track their health with a smart device increase their physical activity an extra 50 minutes per week, and an extra 12 hundred steps are taken daily.

Health alerts can detect potential health problems like irregular heartbeats, but are these smartwatches always right?

"They’re good starting points, but they don't work the same way for everyone,” health psychologist Vanessa Volpe said.

Volpe has a team at North Carolina State University putting smartwatches to the test.

A green light at the back of the device is sent through the skin and reflected back to sensors in the watch, but Volpe says green light reflects differently on different skin tones.

“If you have darker skin, then light will not penetrate and be reflected back to the same degree,” Volpe says.

According to Volpe, this could impact readings for heart rate, blood pressure, and irregular heart rhythms for people of color. 

“The technology itself, the way it was designed, was not taking into account folks with different skin tones — especially folks with darker skin tones,” Volpe said.

Volpe said she sees this discrepancy as a sign of the medical field's failure to grasp the impact of race on health, and hopes her findings will help address racial disparities in healthcare.

Watch the video above for the full story.