What is the most sever form of heat illness?

The most severe form of heat illness is heat stroke, which occurs when the body's temperature regulation fails, leading to a core temperature of 104°F (40°C) or higher. This condition can cause neurological dysfunction, organ failure, and can be life-threatening if not treated promptly. Symptoms may include confusion, seizures, loss of consciousness, and hot, dry skin. Immediate medical attention is crucial to prevent serious complications or death.