Heat stroke and heat exhaustion are two distinct conditions with different symptoms. Heat exhaustion is marked by cool, pale, or flushed skin, headache, nausea, dizziness, and extreme tiredness. If untreated, it can progress to heat stroke, which is a medical emergency. Signs of heat stroke include a very high body temperature, red skin that may be dry or moist, rapid and shallow breathing, a weak pulse, confusion, vomiting, and seizures. Immediate medical attention is necessary for anyone showing signs of heat stroke.