Update: Exertional rhabdomyolysis, active component, U.S. Armed Forces, 2014-2018.

Among active component service members in 2018, there were 545 incident diagnoses of rhabdomyolysis likely due to exertional rhabdomyolysis, for an unadjusted incidence rate of 42.0 cases per 100,000 person-years. Subgroup-specific rates in 2018 were highest among males, those less than 20 years old, Asian/Pacific Islander service members, Marine Corps and Army members, and those in combat-specific or "other/unknown" occupations. During 2014- 2018, crude rates of exertional rhabdomyolysis increased steadily from 2014 through 2016 after which rates declined slightly in 2017 before increasing again in 2018. Compared to service members in other race/ethnicity groups, the overall rate of exertional rhabdomyolysis was highest among non-Hispanic blacks in every year except 2018. Overall and annual rates were highest among Marine Corps members, intermediate among those in the Army, and lowest among those in the Air Force and Navy. Most cases of exertional rhabdomyolysis were diagnosed at installations that support basic combat/ recruit training or major ground combat units of the Army or the Marine Corps. Medical care providers should consider exertional rhabdomyolysis in the differential diagnosis when service members (particularly recruits) present with muscular pain or swelling, limited range of motion, or the excretion of dark urine (possibly due to myoglobinuria) after strenuous physical activity, particularly in hot, humid weather.