What are the symptoms and treatment of heat exhaustion (heat-related illness)?

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From the Guidelines

Heat exhaustion should be treated immediately by moving the person to a cool place, removing excess clothing, and providing cool liquids to drink, as recommended by the 2024 American Heart Association and American Red Cross guidelines for first aid 1.

Key Recommendations

  • Move the person to a cool place immediately
  • Remove excess clothing to help lower body temperature
  • Provide cool liquids to drink, such as water or sports drinks containing electrolytes
  • Apply cool, wet cloths to the skin or have them take a cool bath to help lower body temperature

Importance of Prompt Treatment

Heat exhaustion can rapidly progress to heat stroke, which is a life-threatening emergency, if left untreated 1. Prompt treatment can help prevent this progression and reduce the risk of morbidity and mortality.

Rehydration and Cooling

Rehydration is crucial in treating heat exhaustion, and adults should consume about 1-2 liters of fluid over 2-4 hours 1. Cooling measures, such as cool water immersion or applying cool, wet cloths to the skin, can also help lower body temperature and reduce the risk of heat stroke.

Prevention

Prevention includes staying hydrated, avoiding outdoor activity during the hottest parts of the day, wearing lightweight clothing, and acclimatizing gradually to hot environments 1. By taking these precautions, individuals can reduce their risk of developing heat exhaustion and heat stroke.

From the Research

Definition and Symptoms of Heat Exhaustion

  • Heat exhaustion is part of a spectrum of heat-related illnesses that can affect all individuals, although children, older adults, and those with chronic disease are particularly vulnerable 2
  • Signs and symptoms of heat exhaustion may develop suddenly or over time, and can include nonspecific symptoms such as malaise, headache, and nausea 3
  • Exposure to a hot environment for a prolonged period and performing exercise or work in the heat can overwhelm the body's ability to cool itself, causing heat exhaustion 2

Management and Treatment of Heat Exhaustion

  • Heat exhaustion can be managed by the immediate reduction of heat gain by discontinuing exercise and reducing radiative heat source exposure 2
  • The individual should be encouraged to drink cool fluids and remove or loosen clothing to facilitate heat loss 2
  • In more extreme situations, more aggressive cooling strategies (e.g., cold shower, application of wet towels) to lower core temperature should be employed 2
  • Water immersion techniques (using 1-17 °C water) can rapidly reduce core body temperature in settings where it is feasible 4

Prevention of Heat Exhaustion

  • Heat-related illnesses such as heat exhaustion can be prevented by increasing public awareness of the risks associated with exposure to high temperatures and prolonged exercise 2
  • Programs involving identification of vulnerable individuals, dissemination of information about dangerous heat waves, and use of heat shelters may help prevent heat-related illness 3
  • Prompt recognition and immediate cooling through evaporation or full-body ice-water immersion are crucial in preventing the progression of heat exhaustion to heatstroke 3

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Heat exhaustion.

Handbook of clinical neurology, 2018

Research

Management of heatstroke and heat exhaustion.

American family physician, 2005

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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