Rhabdomyolysis is characterized by the rapid breakdown of overworked intracellular muscle, skeletal muscle cells and the release of toxic fibers into the bloodstream. It is a significant threat to U.S. military members during physical exertion, particularly under heat stress. This report summarizes numbers, rates, trends, risk factors and locations of occurrences for exertional heat injuries, including exertional rhabdomyolysis for 2012-2016.