Recognizing Heat-Induced Illness


Illnesses as a result of exposure to extreme heat include heatstroke, heat exhaustion, heat syncope, heat cramps, heat rashes, and rhabdomyolysis, a medical condition associated with heat stress that is the rapid breakdown and death of muscle.


In 2017, OSHA received reports that 24 workers died from heat stress. Outdoor workers and workers in hot environments are at risk of heat illnesses.


Symptoms of heat illnesses can be difficult to recognize, even for those who are experiencing them. If you or a coworker experiences any of these signs or symptoms, notify a supervisor immediately and seek medical attention:


  • Heatstroke—Confusion, altered mental status; slurred speech; loss of consciousness; hot, dry skin or profuse sweating; seizures; and a very high body temperature. It is important to note that heatstroke can be fatal.

  • Heat exhaustion—Headache, nausea, dizziness, weakness, irritability, thirst, heavy sweating, elevated body temperature, or decreased urine output.

  • Heat syncope—Fainting (short duration), dizziness, or light-headedness during prolonged standing or suddenly rising from a sitting or lying position.

  • Heat cramps—Muscle cramps, pain, or spasms in the abdomen, arms, or legs.

  • Heat rash—Looks like a red cluster of pimples or small blisters and usually appears on the neck, upper chest, groin, under the breasts, and in elbow creases.

  • Rhabdomyolysis—Muscle cramps/pain, abnormally dark (tea or cola colored) urine, weakness, or exercise intolerance. This condition can also be asymptomatic (show no symptoms).