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Heat Disorders

Heat disorders are caused by prolonged exposure to hot temperatures or excessive physical activity, restricted fluid intake, or failure of the body's ability to regulate its temperature. The general term used for heat disorders is hyperthermia.

Heat becomes a problem when humidity, air temperature, and radiant heat combine with hard work to raise body temperature beyond safe limits. Sweat is your main defense. Everyone on the fireline must understand the importance of drinking water often.

There are several terms and types of heat related illnesses which can include heat cramps, heat exhaustion and heat stroke:

Heat cramps are the least serious form of hyperthermia. They are the first sign that the body is having difficulty with increased temperature. Heat cramps are a warning sign that more serious problems may soon develop.

  • Painful muscle spasm, often in the abdomen, back as well as extremities
  • Fatigue
  • Thirst 

Heat exhaustion is more serious than heat cramps. Heat exhaustion results when the body produces more heat than it can dissipate. Inadequate fluid intake can be a major contributing factor. The body may become dehydrated, or its temperature regulation system may begin to fail. 

  • Weakness
  • Extreme fatigue
  • Nausea
  • Headaches
  • Wet, clammy skin
  • Dark yellow or orange urine

Prompt treatment of heat cramps and heat exhaustion is usually successful. Patients recover in a matter of hours or, at most, a day, or two. Heat Stroke poses more serious problems.

Image
Heat Exhaustion and Heat Stroke symptoms

Heat stroke is a medical emergency. Heat stroke is caused by failure of the body’s heat controls.  Whereas heat cramps and heat exhaustion may be treated locally, heat stroke patients should be medevac’d off the line immediately, by air if possible, as their condition may worsen suddenly.

The main characteristic is altered mental status or confusion.

  • Mental confusion
  • Loss of consciousness
  • Seizures
  • Elevated body temperature (sometimes higher than 105.8) 

The presence or absence of sweating is NOT a criterion for heat stroke.  50% of Heat Stroke victims are still sweating.

Brain damage and death may result if treatment is delayed.

The first steps in treating any form of hyperthermia include:

  • Place in cool shaded environment
  • Remove excess clothing and equipment
  • Cool with fanning and/or water dousing
  • Rehydrate orally with cool water only if conscious and can follow directions
    • Provide liquids which contain electrolytes, i.e. Gatorade, etc.
  • Transport to an emergency facility if recovery is not prompt.
  • Individual is not to go back to work that day.
  • If symptoms persist following 10-15 minutes of treatment, suspect heat stroke, and begin more aggressive cooling therapy and immediate transport to an emergency facility.

You can prevent the serious consequences of heat disorders by improving your level of fitness and becoming acclimated to the heat. Maintaining a high level of aerobic fitness is one of the best ways to protect against heat stress. The fit worker has a well-developed circulatory system and increased blood volume. Both are important to regulate body temperature. Fit workers start to sweat sooner, so they work with a lower heart rate and body temperature. They adjust to the heat twice as fast as the unfit worker.

Category
Firefighter Health & First Aid
References
Wildland Firefighter Heat Stress | National Technology & Development Program (f…
Fitness and Work Capacity, PMS 304-2
Incident Response Pocket Guide, PMS 461
Interagency Standards for Fire Aviation Operations (Red Book)

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NWCG Latest Announcements

NEW! Incident Performance and Training Modernization Story Map Now Available

Date: Aug 26, 2025
Questions? Please contact:
National Wildfire Coordinating Group

NWCG is excited to announce the launch of the Incident Performance and Training Modernization (IPTM) Story Map, a new interactive resource that showcases how NWCG is transforming wildland fire training and qualifications through a performance-based system.

Since its launch in 2023, IPTM has made major strides in updating how we manage incident positions:

  • 36 incident positions now have new Incident Position Standards and Next Generation Position Task Books available for field use
  • 6 more incident positions are nearing completion
  • 111 total incident positions are being analyzed through the IPTM initiative

The Story Map guides you through the IPTM process, highlights key accomplishments, and outlines what’s ahead. Whether you are a trainer or a trainee, this tool offers valuable insight into the modernization effort shaping the future of wildland fire training and qualifications.

This effort would not be possible without the contributions of NWCG staff, NWCG committees, and hundreds of subject matter experts across the wildland fire community.

References:

IPTM Story Map

Incident Performance and Training Modernization Webpage

NEW! S-290, Intermediate Wildland Fire Behavior (Blended) Available Now

Date: Aug 15, 2025
Questions? Please contact:
Fire Behavior Subcommittee

NWCG is excited to announce that the S-290, Intermediate Wildland Fire Behavior (Blended) training is now available on the Wildland Fire Learning Portal. S-290 (Blended) training combines online training and instructor-led training components that support individuals working towards any Single Resource Boss or Fire Effects Monitor incident qualifications.

This second course in the series collectively serves to develop fire behavior prediction knowledge and skills, and provides more detailed information on fuels, weather, and topography that affect wildland fire behavior for safety purposes.

Students are required to finish the prerequisite S-190, Introduction to Wildland Fire Behavior, before enrolling in S-290, Intermediate Wildland Fire Behavior (Blended).

References:

S-290, Intermediate Wildland Fire Behavior (Blended)

S-190, Introduction to Wildland Fire Behavior

Wildland Fire Learning Portal

NEW! S-271, Helicopter Crewmember (Blended) Now Available

Date: Aug 14, 2025
Questions? Please contact:
Interagency Helicopter Operations Subcommittee

The S-271, Helicopter Crewmember (Blended) is now available. Developed through the Incident Performance and Training Modernization (IPTM) effort, this training supports individuals working towards Helicopter Crewmember (HECM) incident qualifications. 

S-271, Helicopter Crewmember (Blended) training combines online training and instructor-led training components. This course is designed to provide students with the knowledge and skills necessary to perform the duties of the HECM position, as described in the NWCG Incident Position Standards for Helicopter Crewmember, PMS 350-22.

Any changes to qualification pathways will take effect with the next update of the NWCG Standards for Wildland Fire Position Qualifications, PMS 310-1, scheduled for January 2026.

References:

S-271, Helicopter Crewmember (Blended)

NWCG Helicopter Crewmember (HECM) Position Page

Wildland Fire Learning Portal

Incident Position Standards and Next Generation Position Task Books Now Available for FBAN and LTAN

Date: Aug 13, 2025
Questions? Please contact:
Fire Behavior Subcommittee

NWCG is excited to announce that Incident Position Standards and Next Generation Position Task Books are now available for Fire Behavior Analyst (FBAN) and Long Term Fire Analyst (LTAN).

The Performance Support Packages for these positions were developed as part of the Incident Performance and Training Modernization (IPTM) effort. These resources support trainees, qualified personnel, and evaluators in their respective roles.

Any changes to qualification pathways will take effect with the next update of the NWCG Standards for Wildland Fire Position Qualifications, PMS 310-1, scheduled for January 2026.

References:

NWCG Fire Behavior Analyst Position Page

NWCG Long Term Fire Analyst Page