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

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From the Guidelines

Heat exhaustion is a heat-related illness that requires immediate attention, and the most effective treatment is to move the person to a cool place, remove excess clothing, limit exertion, and provide cool liquids if the person is able to swallow, as recommended by the 2024 American Heart Association and American Red Cross guidelines for first aid 1. The symptoms of heat exhaustion include heavy sweating, cold and clammy skin, fast but weak pulse, nausea, muscle cramps, fatigue, dizziness, headache, and fainting. Heat exhaustion occurs when the body cannot cool itself properly due to high temperatures and dehydration, causing the body's core temperature to rise. Some key measures to take when treating heat exhaustion include:

  • Moving the person to a cool place
  • Removing excess clothing
  • Limiting exertion
  • Providing cool liquids if the person is able to swallow
  • Cooling the person with cold compresses or a cool shower If symptoms don't improve within an hour, it is crucial to seek medical attention, as heat exhaustion can progress to heat stroke, which is a life-threatening emergency 1. It's also important to prevent heat exhaustion by staying hydrated, wearing lightweight clothing, limiting outdoor activity during the hottest parts of the day, taking frequent breaks in the shade, and acclimatizing gradually to hot environments. In cases of heatstroke, immediate active cooling by using whole-body cool- to cold-water immersion for 15 minutes or until neurological symptoms resolve is recommended, as well as activating emergency services 1. Overall, prompt recognition and treatment of heat exhaustion are critical to preventing progression to heat stroke and reducing morbidity and mortality.

From the Research

Symptoms of Heat Exhaustion

  • Heat exhaustion may develop suddenly or over time, with signs and symptoms including malaise, vomiting, and confusion 2, 3
  • Early warning signs of heat exhaustion include flushed face, hyperventilation, headache, dizziness, nausea, tingling arms, piloerection, chilliness, incoordination, and confusion 4
  • Heat exhaustion can be worsened by dehydration due to inadequate access to water or insufficient fluid replacement 2

Treatment of Heat Exhaustion

  • Management of heat exhaustion involves 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
  • Treatment may also involve replacing fluids and electrolytes if needed, and in more serious cases, intravenous hydration may be necessary 3
  • Mild cooling, rest, and hydration are recommended for heat exhaustion 5

Prevention of Heat-Related Illnesses

  • Increasing public awareness of the risks associated with exposure to high temperatures and prolonged exercise can help prevent heat-related illnesses 2
  • Acclimatization, adequate hydration, and avoidance of activities during extreme heat are the most effective measures to reduce the incidence of heat-related illnesses 5
  • Tips to avoiding heat illness include relying not on thirst, drinking on schedule, favoring sports drinks, monitoring weight, watching urine, shunning caffeine and alcohol, and knowing the early warning signs of heat illness 4

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Heat exhaustion.

Handbook of clinical neurology, 2018

Research

Evaluation and treatment of heat-related illnesses.

American family physician, 2002

Research

Treatment of suspected heat illness.

International journal of sports medicine, 1998

Research

Heat-Related Illnesses.

American family physician, 2019

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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