EXERTIONAL HEAT STROKE IN MILITARY OPERATIONS ICE-SHEET COOLING, PREHOSPITAL MANAGEMENT AND FORCE PROTECTION — 2026 UPDATE By DrRamonReyesMD ⚕️

 

EXERTIONAL HEAT STROKE IN MILITARY OPERATIONS

ICE-SHEET COOLING, PREHOSPITAL MANAGEMENT AND FORCE PROTECTION — 2026 UPDATE

By DrRamonReyesMD ⚕️
EMS Solutions International — 2026

INTRODUCTION

Few environmental emergencies in operational medicine allow as little margin for delay as Exertional Heat Stroke (EHS).

A warfighter may deteriorate rapidly from apparently preserved performance to altered mental status, collapse, seizures, multiorgan injury and death.

Military personnel face a particularly important risk because vigorous physical activity generates substantial endogenous heat while uniforms, body armor, helmets, weapons and heavy equipment may impair heat dissipation.

Defense Public Health reports hundreds of military heat casualties and approximately 1–3 heat-related deaths annually among U.S. service members.

The operational principle is straightforward:

SUSPECT EHS → BEGIN RAPID COOLING → EVACUATE.

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RECOGNIZING EXERTIONAL HEAT STROKE

EHS represents the life-threatening end of the exertional heat-illness spectrum.

A core temperature around 104°F / 40°C or higher, particularly when associated with central nervous system dysfunction, is characteristic.

Warning manifestations include:

• confusion;
• disorientation;
• irrational behavior;
• combativeness;
• altered speech;
• ataxia;
• vomiting;
• profound weakness;
• seizures;
• decreased consciousness;
• collapse or coma.

Neurological dysfunction is particularly important because the brain is highly vulnerable during severe hyperthermia.

In the operational environment, waiting for profound unconsciousness before initiating treatment can cost valuable time.

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TIME IS TISSUE

EHS is fundamentally a time-dependent thermal emergency.

Prolonged severe hyperthermia increases the risk of neurological injury, rhabdomyolysis, coagulopathy and renal, hepatic and cardiovascular dysfunction.

Consequently:

COOLING IS TREATMENT.

Evacuation remains essential, but available effective cooling should not be unnecessarily postponed until hospital arrival.

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ICE-SHEET COOLING

Cold-water immersion can provide highly effective whole-body cooling, but a suitable immersion system may not exist at a range, training area, austere location or tactical environment.

The U.S. military therefore uses a practical field-expedient alternative:

ICE SHEETS.

Defense Public Health specifically instructs personnel managing suspected heat stroke to:

Cover the casualty with ice sheets while leaving the face exposed.

Thoroughly soak the sheets before application.

Replace them with fresh ice sheets every six minutes.

Evacuate the casualty immediately.

U.S. Army guidance likewise describes soaking the sheets before application and replacing them every six minutes.

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WHY REPLACE THE SHEETS?

Heat transfer depends partly on maintaining a temperature gradient between the casualty and the cooling medium.

As an ice-water-soaked sheet absorbs heat, it progressively warms and becomes less effective.

Replacing it with another freshly chilled sheet restores that gradient and facilitates continued heat extraction.

The technique therefore should not be viewed as merely placing a wet towel over the casualty.

It is a dynamic cooling procedure.

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OPERATIONAL SEQUENCE

For collapse during strenuous activity in a hot environment:

RECOGNIZE → REMOVE FROM HEAT → EXPOSE → ACTIVELY COOL → ABC/ABCDE → MONITOR → EVACUATE

Remove unnecessary equipment such as helmets, body armor, packs and restrictive clothing when operational circumstances permit.

Airway, breathing, circulation and other immediately life-threatening abnormalities still require management, but unnecessary procedures should not delay rapid cooling.

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HEAT EXHAUSTION IS NOT HEAT STROKE

Heat exhaustion may present with:

• dizziness;
• headache;
• nausea;
• weakness;
• muscle cramps;
• fatigue;
• unsteady gait.

Heat stroke represents a substantially more dangerous syndrome, particularly when CNS dysfunction develops.

Defense Public Health explicitly categorizes EHS as a life-threatening medical emergency.

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CRITICAL DIFFERENTIAL: EXERCISE-ASSOCIATED HYPONATREMIA

Not every collapsed warfighter in a hot environment is simply dehydrated.

Exercise-associated hyponatremia resulting from excessive hypotonic fluid consumption may also cause neurological deterioration.

Defense Public Health warns that additional fluid administration to a hyponatremic casualty may be dangerous. Clues can include excessive previous fluid consumption, repeated clear vomiting, abdominal bloating and large quantities of clear urine.

Therefore:

HEAT CASUALTY ≠ AUTOMATICALLY DEHYDRATION.

More water is not universally the correct treatment.

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PREVENTION: WBGT AND OPERATIONAL RISK MANAGEMENT

Military heat-injury prevention begins long before the casualty collapses.

The Wet Bulb Globe Temperature (WBGT) is used to assess environmental heat stress and guide operational risk management.

Commanders and medical personnel should integrate environmental conditions with:

• workload;
• activity duration;
• equipment and uniform;
• acclimatization;
• hydration and nutrition;
• medications;
• concurrent illness;
• sleep and recovery;
• consecutive days of strenuous activity.

Defense Public Health also recommends planning rapid-cooling resources—including ice sheets—at training locations and ensuring water, medical support and evacuation capability are available.

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HYDRATION WITHOUT OVERHYDRATION

Dehydration impairs performance and increases thermal stress.

Excessive water intake, however, can produce dangerous hyponatremia.

Current Defense Public Health guidance emphasizes following established fluid-replacement and work/rest recommendations rather than indiscriminate drinking.

Operational hydration must therefore be planned, monitored and integrated with nutrition and workload.

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IMPLICATIONS FOR TACTICAL AND AUSTERE MEDICINE

Heat injury reinforces an important principle:

OPERATIONAL MEDICINE EXTENDS BEYOND CABCDE.

Environmental exposure can itself generate rapidly fatal casualties.

Units operating in hot environments should incorporate:

• heat-risk assessment;
• WBGT monitoring when applicable;
• acclimatization;
• work/rest cycles;
• appropriate hydration and nutrition;
• early recognition of CNS dysfunction;
• immediately available cooling equipment;
• ice-sheet capability;
• rehearsed medical evacuation procedures.

Simple equipment combined with correct training can have disproportionate clinical value.

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CONCLUSION

Exertional Heat Stroke is a time-critical medical emergency.

A warfighter developing neurological dysfunction during or immediately after strenuous activity in heat should trigger immediate consideration of EHS.

RECOGNIZE.
REMOVE FROM HEAT.
COOL RAPIDLY.
REASSESS.
EVACUATE.

Where cold-water immersion is operationally unavailable, ice-water-soaked sheets covering the casualty except for the face and replaced approximately every six minutes constitute a field-expedient cooling strategy specifically recommended by U.S. Defense Public Health.

OFFICIAL SOURCES

Defense Public Health — Heat Illness Prevention & Sun Safety

Defense Public Health — Heat-Related Illness Prevention

Defense Public Health — Heat Illness Resources

U.S. Army — Prevent Heat-Related Illnesses and Protect Soldiers

Defense Health Agency — Military Efforts Preventing Severe Heat Illness Cases

Defense Public Health — Fluid Replacement & Work-Rest Guidelines

By DrRamonReyesMD ⚕️
EMS Solutions International — 2026