Update: Exertional rhabdomyolysis, active component, U.S. Armed Forces, 2009-2013.

Among active component U.S. service members in 2013, there were 378 incident episodes of rhabdomyolysis likely due to physical exertion or heat stress (exertional rhabdomyolysis). The annual incidence rates of exertional rhabdomyolysis increased 33 percent during 2009-2013. In 2013, the highest incidence rates occurred in service members who were male; younger than 20 years of age; either Asian/Pacific Islander or black, non-Hispanic; members of the Marine Corps and Army; recruit trainees; and in combat-specific occupations. Incidence rates were higher among service members with homes of record from the Northeast compared to other regions of the United States. Most cases of exertional rhabdomyolysis were diagnosed at installations that support basic combat/recruit training or major ground combat units of the Army or Marine Corps. Medical care providers should consider exertional rhabdomyolysis in the differential diagnosis when service members (particularly recruits) present with muscular pain and swelling, limited range of motion, or the excretion of dark urine (e.g., myoglobinuria) after strenuous physical activity, particularly in hot, humid weather.