1158 Circulation September 22, 2015 biomedical engineering, and medicine and health-related sciences. 16 Mobile devices that permit collection of data in real time are increasingly ubiquitous, enabling researchers to assess multiple behaviors in various contexts and thus inform the development of interventions to prompt behavior change. Technology-supported behavioral health interventions are designed to engage individuals in health behaviors that prevent or manage illness, and they have led to fundamental changes in health practices. 17 In addition to permitting more frequent and convenient community-based assessment of health parameters, these technology-mediated tools support the exchange of health information among consumers and between consumers and health providers, enable health decision making, and encourage positive health behaviors, including self-management and health promotion. 18, 19 Consequently, mHealth technologies are becoming more prevalent, and their use will continue to grow, 20 consistent with the Institute of Medicine’s call to increase the design and testing of health technologies. 21 The ubiquity of mobile devices presents the opportunity to improve health outcomes through the delivery of state-of-theart medical and health services with information and communication technologies. 22 Because of their diverse capabilities and advanced computing features, smartphones are often considered pocket computers. 16 In addition to these devices that can inform and communicate, there are wearable sensors that can be worn for short or extended periods and monitor activity or physiological changes (eg, exercise, heart rate, sleep). These sensors can provide data in real time or save the data to a device for later uploading and review.

The US Food and Drug Administration has a public health responsibility to oversee the safety and effectiveness of medical devices. However, this applies only to applications (apps) that are accessory to regulated medical devices (eg, apps that diagnose a condition). Many mobile apps are not medical devices, meaning that they do not meet the definition of a device under section 201 (h) of the Federal Food, Drug, and Cosmetic Act, and the US Food and Drug Administration does not regulate them. Some mobile apps may meet the definition of a medical device, but because they pose a lower risk to the public, the US Food and Drug Administration intends to exercise enforcement discretion over these devices. Most of the mHealth apps on the market at this time fit into these 2