Heat exhaustion. Heavy sweating, pale and clammy, headache, dizziness, nausea, cramps, fast weak pulse. They are miserable but they are with you.
- Out of the sun, somewhere cool. Lie down, legs raised.
- Loosen clothing. Cool the skin — water, wet cloths, fanning.
- Sips of water if they are fully alert.
- They should improve within half an hour. If they do not, treat it as heat stroke.
Heat stroke is a medical emergency. The difference is the brain: confusion, strange behaviour, slurred speech, unsteadiness, seizure, loss of consciousness. The skin may be hot and dry — or still sweaty, which is why "dry skin" is a bad rule to rely on.
- Call the emergency number.
- Cool them aggressively and immediately. Cooling is the treatment and every minute at temperature causes damage. Cold water immersion where it can be done safely; otherwise cold wet sheets, water over the skin continuously, ice packs to the neck, armpits and groin, and constant fanning.
- Nothing by mouth if they are not fully alert.
- Keep cooling while you wait. Stop when they start shivering strongly or become alert and cooler.
Who is at risk before anybody else. Small children, older people, people working outdoors, people in uniform and body armour, people on medication that affects sweating, and anybody left in a parked vehicle — where the inside temperature rises far faster than people expect.
Source. World Health Organization, Climate change, heat and health, https://www.who.int/news-room/fact-sheets/detail/climate-change-heat-and-health ; European Resuscitation Council, Guidelines 2021, First Aid section, https://cprguidelines.eu/guidelines-2021
What this is not. Reading, not certification.