Heat stress management strategies for firefighters

Heat stress is a challenge for firefighters and emergency services during firefighting operations.
Exposure to high temperatures and intense physical exertion can increase the risk of heat stroke
and heat fatigue.

Implementing effective strategies is essential to ensure the safety and performance of firefighters in
high-risk situations.

What is heat stress and how does it affect firefighters?

Heat stress occurs when the body is unable to dissipate heat generated by physical exertion or the
environment. Symptoms include dehydration, heat exhaustion, muscle cramps and, in extreme
cases, heat stroke, which can be very dangerous.

Firefighters are particularly exposed to this risk due to the combination of high temperatures in
structural and forest fires and prolonged physical exertion in extreme environments.

Thermoregulation in firefighters

Thermoregulation is a natural process in the body that involves the activation of central and
peripheral mechanisms to maintain body homeostasis and constant vital functions. Under normal
conditions, the body uses various mechanisms to dissipate heat and ensure that body temperature
does not reach dangerous levels.

These thermoregulatory mechanisms include radiation, which involves the transfer of energy in the
form of infrared rays between the body and the environment, and convection, which involves the
transfer of heat through particles of air or water. Conduction occurs when heat is transferred
directly between the body and objects in contact, and evaporation through perspiration plays a key
role in removing heat in environments where the ambient temperature exceeds the body
temperature.

Firefighters are exposed to different heat loads depending on the intensity of the fire and proximity
to the heat source. These loads are divided into four levels:

Class I, where the heat flux is less than 1000 W/m² and the temperature does not exceed 100ºC;
Class II, with a heat flux between 1000 and 2000 W/m² and temperatures up to 160ºC; Class III, with
a flux between 2000 and 10000 W/m² and temperatures that can reach 260ºC; and finally Class IV,
where the heat flux exceeds 10000 W/m² and the ambient temperature exceeds 260ºC.

These values reflect the extreme demands placed on firefighters and the importance of effective
protection and recovery strategies to mitigate the effects of heat stress.

Heat stress management strategies

Staying hydrated is one of the most effective strategies for preventing heat stress. It is
recommended that firefighters consume between 500 ml and 1 litre of water per hour of intense
activity, including electrolyte drinks to replenish mineral salts lost through sweating. Excessive
consumption of caffeine or alcohol before and after an operation should be avoided, as these can
contribute to dehydration and impair physical performance.

In addition to hydration, it is important to introduce rest breaks and a system of staff rotation to
minimise overexposure to heat. Rest areas should be located in shaded or air-conditioned areas,
and it is advisable to rotate shifts at regular intervals to reduce heat fatigue. These measures will
allow the body to recover and prevent excessive heat build-up.

The use of appropriate protective equipment also plays a key role in managing heat stress.
Technological advances in PPE have enabled the development of garments that facilitate
ventilation and heat dissipation. It is important that firefighters wear cooling undergarments that
wick away moisture and, where possible, cooling vests or active cooling devices that help to reduce
body temperature.

Training and awareness of heat stress is essential for firefighters to recognise symptoms early and
act in a timely manner. Training should include information on the prevention and treatment of heat
stress, as well as controlled environment drills to improve heat resistance. In addition,
implementing specific heat stress first aid protocols can make a difference in critical situations.

Monitoring vital signs is another effective strategy for early detection of heat stress. Thanks to
technological advances, it is possible to use body temperature sensors embedded in clothing,
mobile apps that alert to signs of overheating, and regular medical assessments to detect heat-
related health problems. These tools help to keep firefighters safe and reduce the risk of
complications from heat stress.

Heat stress management is a key factor in the safety and effectiveness of firefighters during
firefighting operations. Strategies such as adequate hydration, rest breaks, use of optimised
equipment and monitoring of vital signs can significantly reduce the risks associated with exposure
to extreme heat.

References:

1. HEAT STRESS IN FIREFIGHTERS. Retrieved 21 February 2025, from firefighters. info website: URL