What are the symptoms and treatment of heat exhaustion?

Heat Exhaustion: Symptoms and Treatment

Key Symptoms

Heat exhaustion is a moderate heat illness characterized by the inability to maintain blood pressure and sustain adequate cardiac output, with core body temperature less than 104°F (40°C). 1

The cardinal symptoms include:

• Weakness and fatigue 1
• Dizziness and feeling faint 2
• Nausea and vomiting 2, 3
• Syncope (fainting) 1
• Headache 1, 2
• Heavy sweating 2
• Muscle cramps 2

Additional warning signs that may precede full heat exhaustion include flushed face, hyperventilation, tingling arms, piloerection (goosebumps), chilliness, incoordination, and confusion. 4

Immediate Treatment Protocol

Move the person to a cool environment immediately and begin cooling measures without delay. 2

Step 1: Environmental Control

• Remove the person from heat exposure to a cool, shaded area 1, 2
• Remove excess clothing and protective equipment 1, 2
• Limit all physical exertion 2

Step 2: Active Cooling

• Spray or apply cool water to the skin 2
• Use wet towels if available 5
• In more severe cases, consider cold showers or ice-water immersion 5
• Continue cooling for 10-15 minutes 1

Step 3: Rehydration

• Provide cool fluids containing carbohydrates and electrolytes if the person can swallow safely 2
• For exertional dehydration, a 4-9% carbohydrate-electrolyte drink is preferable to water alone 2
• Typical fluid volumes: 100-250 mL (3-8 oz) every 20 minutes for children 9-12 years old, up to 1.0-1.5 L (34-50 oz) per hour for adolescents 1
• In severe cases requiring medical transport, intravenous hydration may be necessary, though serum sodium must be monitored to prevent cerebral edema 3

Critical Distinction: Heat Exhaustion vs. Heat Stroke

The presence of altered mental status (delirium, confusion, convulsions, or coma) indicates heat stroke, not heat exhaustion, and requires immediate emergency medical services activation. 1, 2

Heat exhaustion features:

• Core temperature <104°F (40°C) 1
• Normal mental status (though may have mild confusion) 3

Heat stroke features:

• Core temperature ≥104°F (40°C) 1
• Central nervous system dysfunction (altered mental status, seizures, coma) 1

When to Activate Emergency Services

Call 911 immediately if: 1, 2

• The person collapses or exhibits altered mental status
• Symptoms worsen despite first aid measures 2
• The person cannot swallow fluids safely
• Core temperature exceeds 104°F (if measurable) 1

Return to Activity Guidelines

Anyone experiencing heat exhaustion should not return to practice, competition, or physical activity for the remainder of that session. 1

For heat cramps specifically, do not resume exercise until all symptoms have completely resolved. 2

Common Pitfalls to Avoid

• Do not delay treatment waiting for temperature verification - if clinical signs suggest moderate to severe heat stress, begin cooling immediately 1
• Do not rely on oral temperature - rectal temperature is the gold standard for core body temperature assessment 1
• Do not assume the person will self-diagnose - confusion may prevent recognition of their own condition 4
• Do not give fluids to someone with altered mental status - aspiration risk requires IV hydration instead 3
• Do not overlook medication effects - diuretics and certain drugs can worsen heat illness 6

Special Populations at Higher Risk

Children, elderly individuals, and those with chronic diseases are particularly vulnerable due to impaired heat dissipation mechanisms. 5 Children require especially vigilant monitoring and should receive prompt cooling for 10-15 minutes with hydration if alert enough to drink while awaiting medical assistance. 1