Heat stroke occurs when the body is unable to cool itself by sweating, leaving it unable to regulate its own temperature. Levels can reach 106°F (41.1°C) or higher, leading to brain damage or even death if it isn’t treated quickly and the body temperature is brought under control. Heat stroke is usually caused by physical activity in hot or humid conditions, whether it be outside on a hot, sunny day or inside in a warm environment. Children can also get heat stroke if left in a car on a hot day – temperatures can soar to dangerous levels in a matter of minutes.