When you overexert yourself or wear heavy clothing in hot, humid weather, you run the risk of heat exhaustion. Among its symptoms are cold, clammy, pale skin; heavy perspiration; dizziness, nausea and headache; rapid breathing and pulse; and faintness that may lead to unconsciousness.
If you see someone with these symptoms, make him sit or lie down in a cool spot immediately. Loosen his clothing and remove extra layers. Fan his skin. If he's alert, get him to drink up to 1 pint/ 570ml of water; if he's groggy, don't force him to drink fluids - you could cause choking.
Heatstroke If the condition doesn't improve within 30 minutes, there is risk of heatstroke. Its symptoms are hot, dry, flushed skin; deep, then shallow breathing; a rapid, strong pulse, followed by a rapid, weak pulse; dilated pupils; unconsciousness; twitching muscles; and convulsions.
If you suspect heatstroke, cool down the victim as fast as you can. Take extreme measures: soak towels and sheets in cold water and wrap them around his body. If ice is available, put it in plastic bags and place under his armpits, behind each knee, in the groin, on the wrists and ankles and on the sides of the neck. When the victim's temperature drops to 38°C/100°F, wrap him in a dry sheet. If it rises again, repeat the cooling process.
Call an ambulance or rush the victim, wrapped in wet cloths, to a hospital. If you can't get him to hospital, immerse him in the coldest water possible. Stay with him to prevent drowning.