What Is the Difference Between Heat Exhaustion and Heat Stroke?

Heat exhaustion and heat stroke are both heat-related illnesses that occur when the body cannot adequately cool itself. However, heat exhaustion and heat stroke are not the same thing. Heat stroke is generally more serious than heat exhaustion, so it is important to recognize the difference and seek appropriate treatment.

Symptom differences

Several of the same symptoms, including headache and nausea, occur with heat exhaustion and heat stroke; however, they are typically more severe with heat stroke.

Symptoms of heat exhaustion include, but are not limited to, the following:

• Heavy sweating
• Dizziness
• Fainting
• Weakness, fatigue
• Cold, pale, or clammy skin
• Weak, rapid pulse
• Muscle cramps
• Goosebumps

Symptoms of heat stroke include, but are not limited to, the following:

• A body temperature of 104 degrees Fahrenheit (40 degrees Celsius) or higher
• Altered mental state, including confusion, agitation, slurred speech, irritability or delirium
• Lack of sweating
• Dry, hot skin
• Strong, rapid pulse
• Rapid, shallow breathing
• Seizures
• Coma

Although heat stroke can occur after a period of untreated heat exhaustion, it can also occur suddenly without any preceding symptoms of heat exhaustion.

Treatment differences

Heat exhaustion can usually be treated at home. At-home treatments include the following:

• Seeking a cool location, such as an air-conditioned room or shady area
• Loosening tight clothing
• Putting cool, wet cloths on the skin or taking a cool bath
• Sipping water or a sports drink with electrolytes

If symptoms of heat exhaustion get worse or last longer than an hour, medical attention is advised.

Heat stroke requires emergency medical attention as it can damage brain cells and other internal organs. Emergency medical treatment involves replacing lost fluids and lowering body temperature using cold water, ice packs, or cooling blankets.