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Heat Stress - Heat Related Illness

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Types of Heat-related Illnesses

Heat Stroke | Heat Exhaustion | Rhabdomyolysis |Heat Syncope | Heat Cramps | Heat Rash

Heat Stroke

Heat stroke is the most serious heat-related illness. It occurs when the body becomes unable to control its temperature: the body’s temperature rises rapidly, the sweating mechanism fails, and the body is unable to cool down. When heat stroke occurs, the body temperature can rise to 106°F or higher within 10 to 15 minutes. Heat stroke can cause death or permanent disability if emergency treatment is not given.

Symptoms
Symptoms of heat stroke include:
  • Confusion, altered mental status, slurred speech
  • Loss of consciousness (coma)
  • Hot, dry skin or profuse sweating
  • Seizures
  • Very high body temperature
  • Fatal if treatment delayed

Symptoms of heat stroke include:
  • Confusion, altered mental status, slurred speech
  • Loss of consciousness (coma)
  • Hot, dry skin or profuse sweating
  • Seizures
  • Very high body temperature
  • Fatal if treatment delayed

First Aid
Take the following steps to treat a worker with heat stroke:
  • Call 911 for emergency medical care.
  • Stay with worker until emergency medical services arrive.
  • Move the worker to a shaded, cool area and remove outer clothing.
  • Cool the worker quickly with a cold water or ice bath if possible; wet the skin, place cold wet cloths on skin, or soak clothing with cool water.
  • Circulate the air around the worker to speed cooling.
  • Place cold wet cloths or ice on head, neck, armpits, and groin; or soak the clothing with cool water.

Take the following steps to treat a worker with heat stroke:
  • Call 911 for emergency medical care.
  • Stay with worker until emergency medical services arrive.
  • Move the worker to a shaded, cool area and remove outer clothing.
  • Cool the worker quickly with a cold water or ice bath if possible; wet the skin, place cold wet cloths on skin, or soak clothing with cool water.
  • Circulate the air around the worker to speed cooling.
  • Place cold wet cloths or ice on head, neck, armpits, and groin; or soak the clothing with cool water.

Heat Exhaustion

Heat exhaustion is the body’s response to an excessive loss of the water and salt, usually through excessive sweating. Workers most prone to heat exhaustion are those that are elderly, have high blood pressure, and those working in a hot environment.

Symptoms
Symptoms of heat exhaustion include:
  • Headache
  • Nausea
  • Dizziness
  • Weakness
  • Irritability
  • Thirst
  • Heavy sweating
  • Elevated body temperature
  • Decreased urine output

Symptoms of heat exhaustion include:
  • Headache
  • Nausea
  • Dizziness
  • Weakness
  • Irritability
  • Thirst
  • Heavy sweating
  • Elevated body temperature
  • Decreased urine output

First Aid
Treat a worker suffering from heat exhaustion with the following:
  • Take worker to a clinic or emergency room for medical evaluation and treatment.
  • If medical care is unavailable, call 911.
  • Someone should stay with worker until help arrives.
  • Remove worker from hot area and give liquids to drink.
  • Remove unnecessary clothing, including shoes and socks.
  • Cool the worker with cold compresses or have the worker wash head, face, and neck with cold water.
  • Encourage frequent sips of cool water.

Treat a worker suffering from heat exhaustion with the following:
  • Take worker to a clinic or emergency room for medical evaluation and treatment.
  • If medical care is unavailable, call 911.
  • Someone should stay with worker until help arrives.
  • Remove worker from hot area and give liquids to drink.
  • Remove unnecessary clothing, including shoes and socks.
  • Cool the worker with cold compresses or have the worker wash head, face, and neck with cold water.
  • Encourage frequent sips of cool water.

Rhabdomyolysis

Rhabdomyolysis is a medical condition associated with heat stress and prolonged physical exertion, resulting in the rapid breakdown, rupture, and death of muscle. When muscle tissue dies, electrolytes and large proteins are released into the bloodstream that can cause irregular heart rhythms and seizures, and damage the kidneys.

Symptoms
Symptoms of rhabdomyolysis include:
  • Muscle cramps/pain
  • Abnormally dark (tea or cola colored) urine
  • Weakness
  • Exercise intolerance
  • Asymptomatic

Symptoms of rhabdomyolysis include:
  • Muscle cramps/pain
  • Abnormally dark (tea or cola colored) urine
  • Weakness
  • Exercise intolerance
  • Asymptomatic

First Aid
Workers with symptoms of rhabdomyolysis should:
  • Stop activity.
  • Increase oral hydration (water preferred).
  • Seek immediate care at the nearest medical facility.
  • Ask to be checked for rhabdomyolysis (i.e., blood sample analyzed for creatine kinase).

Workers with symptoms of rhabdomyolysis should:
  • Stop activity.
  • Increase oral hydration (water preferred).
  • Seek immediate care at the nearest medical facility.
  • Ask to be checked for rhabdomyolysis (i.e., blood sample analyzed for creatine kinase).

Heat Syncope

Heat syncope is a fainting (syncope) episode or dizziness that usually occurs with prolonged standing or sudden rising from a sitting or lying position. Factors that may contribute to heat syncope include dehydration and lack of acclimatization.

Symptoms
Symptoms of heat syncope include:
  • Fainting (short duration)
  • Dizziness
  • Light-headedness during prolonged standing or suddenly rising from a sitting or lying position

Symptoms of heat syncope include:
  • Fainting (short duration)
  • Dizziness
  • Light-headedness during prolonged standing or suddenly rising from a sitting or lying position

First Aid
Workers with heat syncope should:
  • Sit or lie down in a cool place.
  • Slowly drink water, clear juice, or a sports drink.

Workers with heat syncope should:
  • Sit or lie down in a cool place.
  • Slowly drink water, clear juice, or a sports drink.

Heat Cramps

Heat cramps usually affect workers who sweat a lot during strenuous activity. This sweating depletes the body’s salt and moisture levels. Low salt levels in muscles causes painful cramps. Heat cramps may also be a symptom of heat exhaustion.

Symptoms
  • Muscle cramps, pain, or spasms in the abdomen, arms, or legs

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

First Aid
Workers with heat cramps should:
  • Drink water and have a snack and/or carbohydrate-electrolyte replacement liquid (e.g., sports drinks) every 15 to 20 minutes.
  • Avoid salt tablets.
  • Get medical help if the worker has heart problems, is on a low sodium diet, or if cramps do not subside within 1 hour.

Workers with heat cramps should:
  • Drink water and have a snack and/or carbohydrate-electrolyte replacement liquid (e.g., sports drinks) every 15 to 20 minutes.
  • Avoid salt tablets.
  • Get medical help if the worker has heart problems, is on a low sodium diet, or if cramps do not subside within 1 hour.

Heat Rash

Heat rash is a skin irritation caused by excessive sweating during hot, humid weather.

Symptoms
Symptoms of heat rash include:
  • Looks like red cluster of pimples or small blisters
  • Usually appears on the neck, upper chest, groin, under the breasts, and in elbow creases

Symptoms of heat rash include:
  • Looks like red cluster of pimples or small blisters
  • Usually appears on the neck, upper chest, groin, under the breasts, and in elbow creases

First Aid
Workers experiencing heat rash should:
  • When possible, a cooler, less humid work environment is best treatment.
  • Keep rash area dry.
  • Powder may be applied to increase comfort.
  • Ointments and creams should not be used.

Workers experiencing heat rash should:
  • When possible, a cooler, less humid work environment is best treatment.
  • Keep rash area dry.
  • Powder may be applied to increase comfort.
  • Ointments and creams should not be used.

Page last reviewed: June 6, 2018
Content source: National Institute for Occupational Safety and Health