Developing a Real-time, Ecologically Sensitive Physical Activity Intervention Using Smartphones and Bluetooth-enabled Pedometers: Feasibility and Initial Efficacy

Lack of physical activity is associated with negative health outcomes, including obesity, diabetes, and cardiovascular disease. A myriad of interventions aimed at increasing daily physical activity (PA) exist. Increasing PA levels has been shown to improve health among patients with cardiovascular and metabolic diseases. Accelerometers and pedometers can be useful tools in such interventions, particularly when used to provide participants with individualized feedback on progress toward PA goals. These programs typically require participants to set PA goals (e.g., number of steps/day), wear pedometers, and record daily activity levels from the pedometers. This process relies heavily on accurate self-reported information and is both time- and effort-intensive for participants, thus limiting acceptability and longer-term viability of this intervention option.

There is an increasing trend in health behavior research to use mobile devices, such as smartphones to provide interventions. These methods - known as Ecological Momentary Interventions [EMI] - are innovative because they allow researchers and clinicians to offered information to people at specific times and in settings when they may be most in need of such support. One way EMI can be tailored is by having participants complete repeated self-report assessments on mobile devices such as smartphones (known as Ecological Momentary Assessment [EMA]), and then using this material to identify times when people are in need of intervention. Although some studies (including recent studies conducted by members of our research team) have developed interventions that use EMA to create real-time interventions that are delivered in daily life, to our knowledge no study has used objective ambulatory assessment data to do so. Using objective data is potentially advantageous because it utilizes passive data collection (requiring little or no input by participants), and thus reduces participant burden and potential concerns regarding accuracy of self-reported data.

The first aim of this study is to establish the feasibility and acceptability of integrating Bluetooth-enabled activity monitor with smartphones to provide real-time feedback regarding physical activity in everyday life. We will evaluate feasibility and acceptability of this intervention method by tracking intervention delivery and participant compliance with EMA. This information will be automatically recorded by smartphone and activity monitor.

The second aim of this work is to provide a preliminary evaluation of the efficacy of delivering real-time feedback based on objectively measured PA. Our primary outcome is number of objectively measured steps. It is expected that participants will increase from their baseline number of steps when receiving personalized feedback and reminders on the smartphones.