Heat exhaustion and heatstroke demand fast recognition and response. Both emerge in hot weather, but heatstroke is a medical emergency requiring immediate ambulance dispatch.
Heat exhaustion symptoms include heavy sweating, weakness, dizziness, nausea, headache, and muscle cramps. Skin stays pale and clammy. Victims may feel faint but typically remain conscious. Move them to a cool place, lie them flat with legs elevated, apply cool water to skin, give sips of water or electrolyte drinks, and monitor closely. Most recover within 30 minutes with these steps.
Heatstroke is far more serious. The body's temperature regulation fails, causing internal heat to spike dangerously. Warning signs shift dramatically. Sweating may stop entirely, skin becomes hot and red, the person may become confused or lose consciousness, seizures can occur, and body temperature climbs above 40°C (104°F). Breathing and pulse quicken.
Call emergency services immediately if heatstroke is suspected. While waiting for help, move the person to a cool environment and cool them rapidly. Use cold water, ice packs on the neck, underarms, and groin where major blood vessels run close to skin, or immerse them in cold water if possible. Remove unnecessary clothing. Keep them lying down with legs raised slightly, unless unconscious.
Never give someone with heatstroke anything to drink. They may not swallow safely.
The distinction matters. Heat exhaustion is treatable at home with basic first aid. Heatstroke kills without swift intervention. Know the difference, act decisively, and call 999 in the UK if unsure. Summer heat peaks in July and August across the Northern Hemisphere, making this knowledge essential for anyone spending time outdoors or caring for vulnerable populations including the elderly, young children, and those with chronic conditions.