The main sign of heat stroke is a core body temperature greater than 105 degrees Fahrenheit; other symptoms include a throbbing headache, light-headedness, dizziness, lack of perspiration despite the heat, nausea, vomiting, cramps, muscle weakness, cramps and red, hot or dry skin. WebMD notes that a rapid heartbeat, whether strong or weak, is another sign of heat stroke, as is rapid, shallow breathing, unconsciousness, seizures and behavioral changes including disorientation, staggering and confusion.
Heat stroke is a very serious condition that constitutes a medical emergency and requires immediate medical attention, warns WebMD. Heat stroke can cause death or damage to the brain and internal organs. While it generally affects those over 50, it can affect people of any age. When heat stroke is suspected, 9-1-1 should be dialed right away and first aid rendered until help arrives.
Heat stroke is generally a progression from other heat-related injuries, including heat cramps, fainting and heat exhaustion, but it can occur in the absence of heat injuries. It results from prolonged exposure to high temperatures, usually with dehydration, the combination of which can lead to a failure in the body's built-in temperature regulation system. In most people, the most distinguishable symptom is a core body temperature elevated above 105 degrees, according to WebMD.
According to WebMD, heat stroke is more likely to occur with older individuals in environments lacking air conditioning or sufficient airflow. Other groups that have an elevated risk of heat stroke including people of any age lacking sufficient water, those with chronic diseases and people who consume great amounts of alcohol.