PROJECT SUMMARY/ABSTRACT The proposed K01 application will strongly support Dr. Raymond Hernandez's long-term career goal of developing tools usable in interventions to promote efficient and effective recovery from strain. In the recovery from work literature, strain refers to effects (e.g., on affect, physiology, fatigue levels, etc.) of exposure to stressors or any other demands. The symptoms of strain can be alleviated with sufficient engagement in recovery activities. If strain is allowed to accumulate however, it can lead to negative outcomes such as increased likelihood and absenteeism and lower job performance. Strain is frequently allowed to accrue because its symptoms are often unobservable and there are no established objective strain measures, making strain easier to ignore. In the US, insufficient recovery from work-related stress and associated strain has been estimated to cost $125 billion annually from productivity losses and healthcare spending. The proposed K01 study aims to perform secondary data analysis on several existing datasets to investigate whether digital health technology tools that measure physiological functions such as heart rate variability (HRV) and performance-based measures such as mobile cognitive testing can serve as objective indicators of strain. This application is in response to the National Institute of Occupational Safety and Health (NIOSH) strategic goal to “promote safe and healthy work design and well-being”, particularly its intermediate goals focused on “Total Worker Health”. It is also in response to the Healthy Work Design and Well-Being cross- sector objective of promoting a sustainable work-nonwork interface. Mentored research towards completion of study aims will be supplemented with structured career development activities. These activities will fill critical gaps in Dr. Hernandez's past training by enabling him to achieve the following career goals: developing knowledge of passively collected physiological data, learning nuances of ambulatory cognitive assessment, obtaining knowledge of factors influencing use of mobile health technologies (e.g., how to promote uptake of mobile technologies by healthcare systems), and professional development for career scientists (e.g., grant writing). I will be supported by a highly qualified mentorship team, and by the outstanding training environment provided to young researchers by the University of Southern California. A desired end outcome is for mobile measures of cognitive performance and HRV to augment existing worker recovery interventions as objective measures of strain levels, usable by occupational health practitioners (e.g., to monitor and document progress in recovery interventions), employers, and employees. An expected intermediate outcome is an R01 proposal for more rigorous validity/usability tests of mobile strain indicators. Expected outputs after completion of this proposal include multiple publications that illuminate the types of HRV/...