Skip to main content

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.

6MFS Suggestion Form


Have an idea or feedback?

Share it with the NWCG 6MFS Subcommittee
 


Follow NWCG on X and Facebook
 


 

Last Modified / Reviewed:

NWCG Latest Announcements

2025 Week of Remembrance

Date: June 27, 2025
Questions?  Please contact:
6 Minutes for Safety Subcommittee

As we approach the 2025 Week of Remembrance (WOR), June 30–July 6, we dedicate this time to reflect on the past incidents from 2015 and honor the fallen through learning. Since its inception in 2014, WOR has honored wildland firefighters who made the ultimate sacrifice while encouraging critical discussions that reinforce lessons learned.

Throughout the week, we encourage thoughtful and generative conversations—whether in briefing rooms or at tailgates—that promote a culture of continuous learning and safety.

References:

2025 Week of Remembrance: Letter to Leadership

Wildland Fire Lessons Learned Center

ETC Equipment Bulletin: 25-003 Flame-Resistant Shirt Survey

Date: June 12, 2025
Questions?  Please contact:
Equipment Technology Committee

The U.S. Forest Service National Technology and Development Program (NTDP) is seeking input on the Forest Service-designed flame-resistant (FR) shirt, currently available through the National Interagency Support Cache system and FedMall.

NTDP is conducting a product review to improve future FR shirt designs. As part of this effort, a short survey is now open for federal employees who have worn any of three recent FR shirt models. Feedback will guide design improvements to better meet the needs of wildland firefighters.

To comply with the Paperwork Reduction Act, responses are limited to federal employees. The survey is open through September 12, 2025. 

References:

NWCG Alerts

ETC Equipment Bulletin: 25-003

NEW! S-130, Firefighter Training (Blended) Now Available

Date: June 10, 2025
If you have questions, please visit our FAQ page. 
If your question is not answered there, you can 
submit your question using our Contact Us form. 
 

The S-130, Firefighter Training (Blended), equips new wildland firefighters with essential skills through a mix of online learning and hands-on training. The course features a required online component and an instructor-led exercise, reinforcing online concepts with practical performance-based training.

The course builds competencies in wildland fire operations, safety, and equipment use, applicable across various operational environments. Both the online component and instructor-led field exercise must be completed to receive a certificate of completion. Students are required to finish the prerequisite S-190, Introduction to Wildland Fire Behavior, before enrolling in S-130, Firefighter Training (Blended).

References:

S-130, Firefighter Training (Blended)

S-190, Introduction to Wildland Fire Behavior

Wildland Fire Learning Portal

EMC Memo 25-001: Interim Rapid Extraction Module (REMS) Training and Qualification Requirements

Date: June 3, 2025
Questions?  Please contact:
Emergency Medical Committee

The Emergency Medical Committee has issued interim guidance for Rapid Extraction Module Support (REMS) teams. Until further notice, Type I and II REMS teams must designate a team leader qualified at Firefighter Type 1 Squad Boss (FFT1) or higher. This temporary change replaces the Single Resource Boss (SRB) requirement, which is currently not feasible due to administrative barriers.

This memorandum does not include any other changes to the NWCG Standards for Rapid Extraction Module Support, PMS 552. This interim change takes effect immediately and will remain in place until further notice.

References:

EMC Memo 25-001: Interim Rapid Extraction Module (REMS) Training and Qualification Requirements

NWCG Standards for Rapid Extraction Module Support, PMS 552