Heat Stress and Health in Firefighting

Heat Stress and Health in Firefighting: Discover its causes, health risks, and key prevention measures to stay safe during intense heat exposure.

Firefighting is recognized as a demanding and dangerous job. Firefighters face not only burns from fires but also extreme heat and strenuous physical activity, leading to fatalities. Sudden cardiac death accounts for about 45% of job-related firefighter deaths annually in the U.S., according to the National Institutes of Health. Additionally, 12-20 hospitalizations per 1,000 firefighters due to chest pain or heart disease occur each year.

Causes of Heat Stress and Its Impact on Cardiovascular Health

Heat stress is the physical condition where the body cannot handle excessive heat without physiological impairment. It can lead to heat stroke, causing symptoms like headaches, dizziness, unconsciousness, and even death. According to OSHA, heat stress risk occurs when a worker’s body temperature exceeds 38°C (100.4°F). Common causes include high temperatures, radiant heat, high humidity, direct contact with hot objects, and intense physical activity.

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Firefighter Exposure to Heat

Firefighters can be exposed to temperatures up to 300°C and high radiant heat for several minutes before experiencing heat stress. Their core body temperature remains elevated hours after exposure, thickening the blood and increasing the risk of harmful blood clots, which, along with environmental stress and dehydration, raise the risk of heart disease and sudden cardiac death. In 2016, there were 2,475 heat stress injuries among firefighters reported by the NFPA.

Body’s Failure to Regulate Temperature

Normally, the body cools itself by expanding blood vessels and sweating. However, protective gear worn by firefighters disrupts normal thermoregulation, trapping heat inside. This leads to heat stress disorders.

Recognizing Heat Stress Disorders

Heat Stroke

Heat stroke is the most serious heat stress disorder, occurring when the body’s automatic regulation fails, causing a critical rise in body temperature. Symptoms include confusion, irrational behavior, unconsciousness, seizures, lack of sweating, hot and dry skin, and extremely high body temperature. Immediate professional treatment is necessary as it can be fatal.

Heat Exhaustion

Heat exhaustion symptoms include headaches, nausea, dizziness, fatigue, thirst, and fainting. It is severe but treatable. It can be mistaken for other heat stress disorders like heat syncope or heat collapse.

Heat Cramps

Heat cramps are muscle spasms in the abdomen, arms, or calves, often caused by electrolyte imbalance due to sweating and inadequate hydration. Firefighters need to stay hydrated, as inadequate replacement of water lost through sweat can lead to excessive sodium in the body. In extreme conditions, sodium loss can occur, and sports drinks are effective in minimizing physiological impairment during recovery.

Heat Rash

Heat rash, the most common issue for firefighters, appears as itchy red bumps due to unevaporated sweat on the skin. It typically resolves in cooler environments.

Preventive Measures

Removing Gear: Actively remove heavy PPE in summer to prevent body temperature from exceeding 40°C. In non-critical situations, take off PPE and cool down.
Cooling the Body: Cool large blood vessels near the skin, like those in the neck and armpits, using water from pump trucks.
Hydration: Drink water every 15-20 minutes, regardless of thirst. Sports drinks are effective for recovery.
Heat Acclimatization: Acclimate the body to high temperatures through exercise, half-body baths, saunas, and reducing air conditioning use.

Reference page: “Key fire characteristics: combustion elements, smoke risks, toxic gases, and safe firefighting techniques.”

References　National Fire Protection Association (NFPA)

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Heat Stress and Health in Firefighting