Abstract Young adults report the highest rates of heavy drinking and are a priority population for alcohol prevention and intervention efforts. Alcohol strategies that leverage their other health concerns and utilize technology may offer an innovative solution. Taking this approach, we conducted the first preliminary test of a mobile sleep intervention to engage heavy-drinking young adults in treatment and showed promising effects on drinking. Data from this pilot study and our current follow-up study (R34AA026021) have generated new hypotheses and directions for refinement of this mobile intervention. Specifically, heavy-drinking young adults want feedback about their health status and how they can improve it by reducing their drinking and improving their sleep. Thus, to optimize the effectiveness of personalized alcohol feedback for young adults, we propose to embed it within a more comprehensive health feedback program and connect alcohol use not only to sleep but also to robust, non-invasive health biomarkers – resting heart rate (RHR) and heart rate variability (HRV), with the latter particularly affected by heavy alcohol use and potentially by poor sleep. In addition, we will incorporate new sensor technology that utilizes photoplethysmography (PPG) to obtain daily, passive collection of HRV, RHR, and sleep that can be connected to mobile apps to provide feedback based on these data. In one preliminary study of a PPG sensor and integrated mobile app, users who noted a link between their alcohol use and sleep/health data were motivated to reduce their drinking. Therefore, PPG technology warrants further study for alcohol prevention and early intervention. The current proposal will conduct the first controlled test of a feedback/brief advice intervention targeting HRV, RHR, and sleep via PPG sensors and electronic daily diaries for heavy-drinking young adults and will leverage the benefits of a marketed PPG sensor and mobile app, OURATM. We will randomize subjects to: (1) Assessment (n=30) or (2) Feedback (n=30). All subjects will wear an OURA™ and complete daily electronic diaries for 6 weeks and attend follow- ups at Weeks 6 and 10. Subjects in Assessment will only monitor their health/behaviors and will not receive any health feedback or advice. Subjects in Feedback will monitor their health/behaviors and receive daily health information from the OURA™ app as well as bi-weekly alcohol-related health feedback/advice that we derive from the OURA™ and diary data: (1) summaries of alcohol use and the links between drinking and OURA™ health biomarkers and (2) evidence-based brief alcohol and sleep advice tailored to this data. This study will yield important preliminary data to support a larger investigation of this novel approach with heavy- drinking young adults. Heavy-drinking young adults may be ideally suited for mobile health feedback interventions that incorporate alcohol content given their preference for technology and infrequent alcoh...