What is the most severe form of heat illness called?

The most severe form of heat illness is known as heat stroke. This condition occurs when the body's temperature regulation fails, typically after prolonged exposure to high temperatures or excessive physical exertion in hot conditions. In heat stroke, the core body temperature rises to critical levels, often exceeding 104°F (40°C). This can lead to multi-organ dysfunction and central nervous system impairment, manifesting as altered mental status, confusion, seizures, or even coma.

Heat stroke requires immediate medical intervention and is a life-threatening emergency. The body’s ability to sweat becomes overwhelmed, and signs of illness may progress rapidly if not treated promptly and effectively.

In contrast, heat exhaustion involves heavy sweating and a significant loss of water and salt, but it does not result in the severe complications associated with heat stroke. Heat edema refers to swelling in the extremities (usually the feet and ankles) due to the body's reaction to heat, while heat cramps consist of painful muscle contractions due to electrolyte imbalance from sweating. Hence, heat stroke is recognized as the most critical and life-threatening condition among heat-related illnesses.