The World Health Organization (WHO) describes heatstroke as a potentially fatal medical emergency and says immediate medical help and aggressive cooling are required. WHO directs bystanders to call emergency services, move the person to shade or air conditioning, remove unnecessary clothing and cool the body while help is on the way.

Do not wait for a temperature reading before acting when severe neurological symptoms appear after heat exposure. Heatstroke can occur with dry skin or continued sweating, so the absence of one familiar sign does not make home observation safe.

Confusion, seizures or collapse require emergency care

Call the local emergency medical service if a person exposed to heat becomes confused, speaks unclearly, has a seizure, loses consciousness or cannot coordinate movement. The US Centers for Disease Control and Prevention (CDC) lists confusion, altered mental status, slurred speech, seizures and coma among heatstroke signs and warns that delayed treatment can be fatal.

Begin cooling immediately after help has been summoned. Stay with the person, watch breathing and responsiveness, and follow the emergency dispatcher's instructions. If the person is unconscious but breathing, WHO advises placing them on their side; if breathing is absent or abnormal, follow the dispatcher's cardiopulmonary resuscitation instructions.

Do not force water or another drink into the mouth of anyone who is confused, drowsy, having a seizure or unconscious. Swallowing may be unsafe. A person with suspected heatstroke needs urgent medical assessment even if cooling appears to improve alertness.

Cold packs are placed near a person's neck and armpit during first aid (illustrative image)

Use cold-water immersion when it is safe and practical

Move the person away from direct heat and remove excess clothing and equipment. If a tub or other safe container is available, immerse as much of the body as possible in cool or cold water while keeping the airway clear. One helper must continuously support and monitor the person in the water.

The CDC Yellow Book identifies an ice bath as the fastest field-cooling method and says emergency evacuation should be activated without delaying cooling. WHO likewise includes cold-water immersion when it is possible and safe. These recommendations do not make an unattended bath safe for a confused or unconscious person.

If immersion is unavailable, wet the skin or clothing with cool water and keep air moving across the body with a fan or manual fanning. Apply cold wet cloths or cold packs to the head, neck, armpits and groin while cooling as much skin as possible. Continue monitoring until trained responders take over.

A person outdoors offers water to another person during hot weather (illustrative image)

Heat exhaustion allows fluids only when swallowing is safe

Heavy sweating, weakness, headache, nausea, dizziness and thirst can occur with heat exhaustion. Move the person to a cool place, loosen clothing and use wet cloths or a cool bath. A fully alert person who can swallow normally may take small sips of water or an oral rehydration drink.

WHO advises rest in a cool place and water for dizziness, weakness, intense thirst or headache, and an oral rehydration solution for painful muscle spasms. Vomiting, worsening symptoms, confusion, collapse or failure to improve requires medical assessment rather than continued oral hydration at home.

Fever medicine does not replace rapid cooling

Do not delay water-based cooling while looking for medicine. WHO says fever-reducing medicines should not be given for suspected heatstroke. Heatstroke results from failed heat control rather than the mechanism that produces an ordinary fever.

A family helps an older adult rest and drink water in a cool room (illustrative image)

Children, pregnancy and chronic illness require separate judgment

Infants and children

Children may not describe confusion, dizziness or swallowing difficulty reliably. Move a child with possible heat illness to a cool place and begin cooling, but seek emergency help immediately for altered behavior, a seizure, collapse or reduced responsiveness. Never leave a child unattended in water during immersion cooling.

Pregnancy

WHO says pregnant people and their babies can be affected by heat, depending on the exposure's frequency, intensity and duration. APPI News could not find a separate emergency cooling sequence for pregnancy in the cited WHO and CDC public guidance. A pregnant person with suspected heatstroke still needs immediate cooling and emergency assessment, while questions about fluids or medicines should go to the responding clinician.

Older adults, chronic illness and regular medicines

WHO says age and health status shape vulnerability to heat and that heat can worsen cardiovascular, respiratory, kidney, metabolic and mental health conditions. The emergency signs and need for immediate cooling do not change; people in these groups should contact a clinician when heat-related symptoms appear.

US CDC clinical guidance says diuretics, anticholinergic drugs and some psychiatric medicines can increase heat-related risk through effects on thirst, sweating, circulation or fluid balance. Do not stop, skip or change a regular medicine during hot weather without advice from the prescribing clinician.

An older adult rests in an air-conditioned room with water and medicines on a table (illustrative image)

Frequently asked questions

What should happen first when heatstroke is suspected?
Call the local emergency medical service, move the person to a cooler place, remove unnecessary clothing and begin rapid cooling. Do not delay cooling while waiting for transport.

What is the fastest cooling method?
The CDC Yellow Book identifies ice-water immersion as the fastest field method. Use it only when the person can be continuously supported and monitored; otherwise wet the skin and use moving air, cold wet cloths or cold packs.

Can a person with suspected heatstroke drink water?
Do not give anything by mouth when confusion, drowsiness, seizure, unconsciousness or swallowing difficulty is present. Small sips are reserved for a fully alert person with milder heat-exhaustion symptoms who can swallow normally.

Should fever-reducing medicine be used?
No. WHO advises against fever-reducing medicines for heatstroke. Emergency help and physical cooling are the priorities.

Should cooling stop if the person seems better?
Keep monitoring and follow the emergency dispatcher's instructions. Suspected heatstroke still requires urgent medical assessment because serious complications may not be visible at the scene.