Heat Exhaustion: Recognition, Cooling, Hydration, and Monitoring

What Heat Exhaustion Is (and What It Is Not)

Heat exhaustion is a heat-related illness caused by the body struggling to cool itself, often after prolonged heat exposure, physical exertion, dehydration, or a combination of these. The person is typically overheated but still sweating, and their circulation is working hard to move heat to the skin for cooling. Heat exhaustion can worsen into a life-threatening emergency if cooling and hydration do not improve symptoms.

In first aid terms, treat heat exhaustion as a condition that requires active cooling, careful hydration, and close monitoring. Your goal is to reduce heat load, restore fluids/electrolytes safely, and watch for signs that the situation is escalating.

Structured Assessment: What to Check and How to Phrase It

Use a consistent, repeatable assessment so you can notice improvement or deterioration. A simple structure is: appearance → sweating → temperature → mental status → key symptoms.

1) Appearance

• Look: flushed or pale, tired, slumped posture, unsteady standing.
• Ask: “Do you feel like you might faint if you stand?”
• Note: inability to continue activity is a common clue.

2) Sweating

• Look/feel: heavy sweating, damp clothing, sweaty skin.
• Why it matters: sweating suggests the body is still attempting to cool; however, sweating alone does not guarantee safety.

3) Temperature (practical check)

• Touch: skin may feel hot and moist.
• If a thermometer is available: record the number and time. A rising temperature despite cooling efforts is concerning.
• Tip: do not delay care to obtain a temperature reading.

4) Mental status

• Check: alertness, orientation, ability to answer simple questions.
• Ask: “What’s your name? Where are we? What were you doing?”
• Red flag: confusion, unusual behavior, or reduced alertness suggests escalation.

5) Key symptoms to screen (use a checklist)

• Dizziness/lightheadedness
• Nausea (with or without vomiting)
• Headache
• Rapid pulse (fast heartbeat, may feel “pounding”)
• Weakness (especially generalized weakness or inability to walk steadily)

Practical phrasing: “Tell me what you’re feeling: dizzy, nauseated, headache, weak, or heart racing?”

Action Protocol: Cooling + Hydration + Safe Positioning

Follow this sequence. It is designed to be easy to remember and to reduce the chance of missing a critical step.

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Step 1: Stop activity and move to a cooler environment

• Move the person to shade, an air-conditioned space, or at least away from direct sun and hot surfaces.
• If indoors, aim for a spot with airflow (fan, open area) and remove them from crowded heat sources.

Step 2: Loosen clothing and reduce heat trapping

• Loosen or remove unnecessary outer layers.
• Remove hats/helmets and open collars.
• Help them sit or lie down to reduce fainting risk.

Step 3: Apply active cooling (cool water + airflow)

• Apply cool wet cloths to skin (neck, armpits, groin, and along the torso are effective areas).
• Fan the person continuously to increase evaporation.
• If available, use a cool shower or sponge bath with cool water.
• Avoid: ice-cold immersion if the person is shivering or uncomfortable; shivering can generate heat and reduce cooling efficiency.

Step 4: Encourage slow sipping of fluids (only if fully alert)

• If the person is awake, alert, and able to swallow normally, offer small, frequent sips.
• Use a pacing cue: “Small sips every 30–60 seconds.”
• Pause if nausea worsens.

Step 5: Position safely

• If dizzy or faint: have them lie down with legs slightly elevated (if comfortable and no injury concerns).
• If nauseated: place them on their side or in a position that protects the airway if vomiting occurs.
• If they must sit: support their back and keep them from slumping forward.

Hydration Choices: Water vs Electrolytes (and What to Avoid)

Best options when the person is fully alert and not vomiting

• Electrolyte drink (oral rehydration solution or sports drink): helpful when sweating has been heavy or prolonged, because it replaces both fluid and salts. This is often the preferred choice if available.
• Cool water: acceptable and beneficial, especially if electrolyte drinks are not available. Pair with salty snacks if appropriate and tolerated.

Practical guidance for choosing

• If symptoms began after long sweating/exertion and the person looks depleted: choose electrolytes if possible.
• If the episode is mild and access is limited: water is still better than delaying hydration.
• If the person is cramping, very sweaty, or has had hours of heat exposure: prioritize electrolytes over plain water alone.

What to avoid

• Alcohol: worsens dehydration and impairs judgment.
• Very large volumes quickly: can trigger vomiting; use slow sips.
• Highly caffeinated energy drinks: may worsen palpitations and nausea in some people.

When to Avoid Oral Fluids

Do not give oral fluids if any of the following are present, because of choking/aspiration risk or inability to keep fluids down:

• Vomiting that is ongoing or repeated
• Reduced alertness, confusion, or inability to answer simple questions
• Trouble swallowing, coughing/choking with sips, or inability to sit up safely
• Severe weakness where the person cannot hold the cup or coordinate swallowing

In these cases, focus on cooling and urgent medical evaluation.

Monitoring Timeline: Reassess Every 5–10 Minutes

Heat exhaustion care is not “set and forget.” Improvement should be noticeable with cooling and hydration. Use a simple reassessment loop every 5–10 minutes and document mentally (or on a phone note) what changes.

What “improving” looks like

• More alert, clearer speech, better focus
• Less dizziness when sitting up
• Nausea easing and able to tolerate small sips
• Pulse feels less rapid
• Skin feels cooler with ongoing cooling measures

Escalation Triggers: When to Seek Urgent Help

Escalate to emergency services or urgent medical evaluation if any of the following occur at any time:

• Altered mental status: confusion, agitation, unusual behavior, fainting, or reduced responsiveness
• Persistent vomiting or inability to keep fluids down
• Worsening symptoms despite cooling (increasing headache, dizziness, weakness)
• Very rapid pulse that does not slow with rest and cooling, or chest pain/palpitations that are concerning
• Hot skin with decreasing sweating or a sense that the person is “getting hotter,” not cooler
• Signs of collapse: cannot stand/walk safely, repeated near-fainting
• No meaningful improvement within 20–30 minutes of active cooling and appropriate hydration

Escalation script (useful in real situations)

“We have a person with suspected heat exhaustion. They were exposed to heat/exertion and now have dizziness/nausea/weakness and a rapid pulse. We moved them to shade/AC and started cooling. Their mental status is [normal/altered], they are [able/unable] to keep fluids down, and symptoms are [improving/not improving/worsening] after [X] minutes.”

Practical Scenario: Putting the Protocol Together

Example: A runner finishes a hot outdoor event and sits down looking pale and sweaty, saying they feel dizzy and nauseated.

• Assess: sweaty skin, hot to touch, answers questions appropriately but feels lightheaded; pulse is fast.
• Act: move to shade/AC, loosen clothing, apply cool wet cloths to neck/armpits, fan continuously.
• Hydrate: because they are fully alert and not vomiting, give electrolyte drink in small sips every 30–60 seconds.
• Position: lie down with legs slightly elevated until dizziness improves.
• Monitor: reassess at 5–10 minutes; if nausea worsens or vomiting starts, stop oral fluids and escalate care.