You may be able to earn money while getting healthier with your fitness tracker

Step by step, fitness trackers keep up with our every move and in some cases, our sleep, heart rate, blood pressure and more.

Wearing the device might help you get in better shape, but it could also earn you an extra couple of dollars if your employer or insurance company is among those incentivizing your wellness.

"They'll either offer you a decreased rate, or they will offer you money in a Federal savings account, or along those lines.. some sort of discount in order to help offset costs," says Dr. Andrew Boyd, an associate professor of Biomedical and Health Information Sciences.

The plans are typically voluntary and offer free or discounted wearable devices. But Boyd says you may want to step carefully before agreeing to share this information.

"This data can reveal more information about you than many people realize. Your heart rate data sounds innocuous but it's actually quite revealing."

He says it's important to find out what information is being shared and how it will be used. The fear is it may lead to a rate hike or the information may tell companies you're not worth the risk of insuring in the future, especially if current health laws are repealed.

"It's being used to promote wellness. Great. But how do we prevent future insurance companies or future employers from using it to discriminate against you? There isn't a specific protection yet to limit this technology," Boyd says.

In the meantime, Boyd says the data is already being used in criminal cases and police investigations.

Medical experts suggest asking yourself if the company offering the incentive is one you would trust with your personal information down the road.

"There are lots of honorable companies who will use the data exactly as promised but sometimes, some companies don't," he says.

FitBit claims users are in control of their data at all times and customers have the option to deny access to their information "if and when" they decide they no longer want to share it with their employers or anyone else.