A number of different devices, including smart phones, smart watches or other fitness trackers (Fitbit, Nike+) keep track of how far we walk, how many flights of stairs we climb and how many hours and how well we sleep at night. This type of data is not only extremely personal and revealing, but the data is also extremely valuable. As we begin to track our exercise and sleep patterns with wearable devices to better understand our health, it’s important to ask: where is our fitness and sleep data going?

For instance, according to CNN Money, the life insurance company John Hancock announced that they would start offering discounts on insurance plans if individuals would “wear a fitness tracker that measures your footsteps, heart rate or body movements.” If individuals sign up for the plan with John Hancock, then they will receive a free Fitbit monitor. The program is designed to encourage customers to live healthier lives, which would benefit the customer and the insurance company’s bottom line.

While representatives from John Hancock have stated that they will not “sell or share health data to any other entity,” as reported by CNN, it is important for individuals to question and analyze the use of fitness and sleep data. The positive outcomes from collecting this data are immense for individuals making decisions to improve their health, but the potential downside to storing fitness data in a cloud is the information can be revealed to insurance companies or other organizations. Individuals may not want their insurance or health providers to access this type of information.

For example, fitness bands that help measure your sleep patterns can also reveal other data that most people do not want to reveal (i.e., how often they have intercourse). Fitness bands have different types of accelerometers that measure change in position and velocity. The activity patterns of sleep versus sex would obviously be different, and it would allow data analysts to infer or recognize the behavior. As individuals upload their data into the cloud, who is going to develop algorithms to figure out other sensitive data about the customers?

Also, if your partner has signed up for the same life insurance plan as you, coordination of the data between two individuals with a Fitbit could lead to an easier application of algorithm detection. While insurance companies will likely be discreet about the algorithms used to detect sensitive data, who will be the first divorce lawyer to reveal infidelity in court proceedings?

As we look to the mobile cloud and pose questions of privacy and appropriate use of information, we need to read and examine data use agreements, no matter how tedious. Individuals may find answers to the following essential questions: Who does the company share an individual’s fitness data with? Is any of the shared data identifiable? What is the purpose of the data? How often can the company change the terms of use of uploaded data if new algorithms and theories come out?

In the meantime, as these questions are sorted out, individuals can take certain precautions with their fitness and sleep devices to safeguard privacy of data. Remember to remove your smart phone, smart watch or other activity tracker while engaging in activities that you would like to keep private.

However, if you always remove these trackers when you engage in private activities, the fact of removing the band, watch or smart phone might also reveal additional information. Turning off the trackers could still reveal data if individuals are engaging in something private, and even the absence of data can provide valuable insight into your daily life. We are approaching a time in civilization where both the presence of data and lack of data will reveal more about us than we’ve ever previously been comfortable sharing.

The strength of the mobile cloud is accessing essential information about data from the breadth of human experience at your fingertips anywhere in the world, and it can provide incredible value to individuals who are trying to live healthier lives. Unfortunately, to use this information, we also reveal more data about ourselves than initially anticipated. We need to determine what is and what is not an appropriate use of mobile and human tracking within wearable devices and fitness data.

Andrew Boyd is an Assistant Professor of Biomedical and Health Information Sciences at the University of Illinois at Chicago.