Cardiopulmonary symptoms of shortness of breath and decreased exercise tolerance after return from deployment are a major concern for many veterans of Iraq and Afghanistan. While much of the focus has been on burn pit exposure and particulate matter as causal factors, there is growing evidence supporting a contributing role of blast-related lung injury. Acute blast overpressure (BOP) lung injury resulting in gross injury is well established. This project will address the less known, possible long-term, or latent effects of less severe BOP lung injuries. We plan to target veterans deployed to Iraq and Afghanistan with exposure to blast injuries of varying severity and invite them to participate in a multi-day cardiopulmonary evaluation. Specifically, we hope to characterize the severity and burden of mild BOP lung injury in Iraq/Afghanistan veterans and determine the association between BOP exposure with physiological, peripheral blood, and CT based markers of cardiopulmonary function. This is the third annual summary and substantial progress has been made in recruitment and data collection. A no cost extension was requested and approved.