Heat Exhaustion

Heat exhaustion is excessive loss of salts (electrolytes) and fluids due to heat, leading to decreased blood volume that causes many symptoms, sometimes including fainting or collapse.

Heat exhaustion is more severe than heat cramps. Fluids and salts are more depleted, and symptoms are more severe.

Symptoms and Diagnosis

Dizziness, light-headedness, weakness, fatigue, headache, blurred vision, muscle aches, or nausea and vomiting may develop. A person may feel faint or even lose consciousness when standing. Drenching sweats are common. Mild confusion may develop. The heart rate and breathing rate may become rapid; blood pressure may become low. Body temperature can be normal or high but not higher than 104° F.

Heat exhaustion usually can be diagnosed on the basis of the symptoms and occurrence after exposure to heat.

Treatment

Treatment involves replacing fluids (rehydration) and salts and removing the person from the hot environment. If symptoms are mild, sipping cool, slightly salty beverages every few minutes may be all that is needed. Removing or loosening clothing and applying wet cloths or ice packs to the skin also aid cooling.

If symptoms include loss of consciousness, confusion, rapid breathing or heartbeat, or low blood pressure, then fluids are given intravenously. After rehydration, a person usually recovers rapidly and fully. If left untreated, heat exhaustion can lead to heatstroke.