Heatstroke, also called sunstroke, is a dangerous illness that occurs when a person’s body temperature rises above 106 °F in a matter of minutes.

Spending time outdoors in high temperatures puts you at risk for heat-related illness, especially during work or physical activity. In very hot, humid weather, sweating isn’t always enough to cool you down.

This causes your body temperature to skyrocket to life-threatening levels. Here’s how to detect heatstroke and what you can do to treat the illness fast.

What are the early signs of heatstroke?

At first, you might not realize you’re on your way to heatstroke. You may experience heat exhaustion, which occurs when your body gets too hot. Because heat exhaustion may develop into heatstroke if you don’t cool off quickly, watching for signs of heat exhaustion can help you stop heatstroke. Common signs of heat exhaustion include heavy sweating and a rapid pulse.

If you develop heatstroke, you may experience symptoms including:

• Confusion
• Dizziness
• Headache
• High body temperature
• Hot, red, dry skin
• Loss of consciousness
• Nausea

If you or someone around you has these symptoms, act quickly to get help.

What to do if you suspect heatstroke

If you suspect heatstroke, getting immediate care is important to prevent organ failure, brain damage or even death. Call 911 for medical assistance.

If you are able, move to a shady area. Ask for cool water or cloths to lower your temperature. If emergency medical personnel are delayed, whoever is assisting you should call your nearest emergency department for further treatment instructions.

How can you prevent heat stroke?

Anyone can get heatstroke. But some people are at increased risk. Take extra care in the sun if you are:

• Age 65 or older
• Overweight
• Take certain medications, such as diuretics and medicines, to manage blood pressure (Ask your physician if your prescribed medication increases your risk of heatstroke.)

Taking extra precautions, especially if you’re at risk, can help prevent heatstroke. Drinking plenty of water, pacing your activities with breaks in the shade or air conditioning, and having a work or play buddy around to check in on you are all great ways to cut your risk of developing heatstroke.

Know what to expect in the ER if a medical emergency, such as heatstroke, sends you for immediate care.