Update: Heat illness, active component, U.S. Armed Forces, 2019

In 2019, there were 507 incident cases of heat stroke and 2,174 incident cases of heat exhaustion among active component service members. The overall crude incidence rates of heat stroke and heat exhaustion were 0.39 cases and 1.65 cases per 1,000 person-years, respectively. In 2019, subgroup-specific rates of incident heat stroke were highest among males, those less than 20 years old, Asian/Pacific Islanders, Marine Corps and Army members, recruit trainees, and those in combat-specific occupations. Subgroup-specific incidence rates of heat exhaustion in 2019 were notably higher among service members less than 20 years old, Asian/Pacific Islanders, Marine Corps and Army members, recruit trainees, and service members in combat-specific occupations. During 2015-2019, a total of 348 heat illnesses were documented among service members in Iraq and Afghanistan; 7.5% (n=26) were diagnosed as heat stroke. Commanders, small unit leaders, training cadre, and supporting medical personnel must ensure that the military members whom they supervise and support are informed about the risks, preventive countermeasures, early signs and symptoms, and first-responder actions related to heat illnesses.