With hot and humid weather during many months of the year, heatstroke is a real concern in America.

And while dramatic weather events like tornadoes and floods get lots of media attention, around 618 people are killed by extreme heat every year in the U.S. Learn to recognize the signs of heatstroke and know what to do if it occurs:

What is heatstroke?

Heatstroke is a result of heat exhaustion that's not treated, Dr. Jonathan Kim, a sports cardiologist and assistant professor at Emory University, told the AJC. It results from being exposed to high temperatures for a long time and is often combined with dehydration. As a result, your body's temperature control system fails.

» Keep track of the temperature at ajc.com/weather.

Heat exhaustion is more common than heatstroke and is characterized by the following symptoms:

  • Heavy sweating
  • Cold, pale and clammy skin
  • Dizziness
  • Nausea or vomiting
  • Muscle cramps
  • Fast, weak pulse

If you experience these conditions, Dr. Kim recommends getting into an air-conditioned building if possible, or sitting under a fan and using cold towels under your armpits and on your groin and back. The towels should be replaced with cold ones before they get warm. You should also rehydrate by drinking plenty of water.

Anyone can get heatstroke, even people in good physical shape who are used to getting exercise, Kim said. However, people who aren't in good physical condition, as well as the very young and the elderly can face an increased risk. Certain medications — including diuretics and medicines used to treat allergies, high blood pressure or heart disease — can also increase your chances of developing heatstroke.

What are the symptoms of heatstroke?

Many of the symptoms of heatstroke are similar to symptoms associated with heat exhaustion. However, the following signs may indicate that you're dealing with heatstroke:

  • High body temperature (103°F or higher)
  • Hot, red, dry or damp skin
  • Fast, strong pulse
  • Feeling confused

In most cases of heat exhaustion, people sweat a lot, but if you have heatstroke, you'll actually be dry. This should be taken as a rule of thumb, but there are exceptions.

How can you avoid heatstroke?

WebMD recommends the following:

  • Watch the heat index – The heat index measures how hot you feel when the air temperature is combined with the effects of relative humidity. When the relative humidity is at least 60 percent, it hinders your body's ability to cool itself through sweat evaporation. Stay inside if possible when the heat index is too high.
  • Wear the right clothing – Lightweight, light-colored, loose-fitting clothing is best, and you should top it off with a wide-brimmed hat to protect your head and face.
  • Use sunscreen – Apply sunscreen liberally, and reapply it often, especially if you've been in the water or are sweating. It should have a sun protection factor (SPF) of at least 30.
  • Drink plenty of fluids – Besure to stay hydrated and replenish fluids by drinking plenty of water, fruit juice or other beverages. If you're outside and are exercising and sweating a great deal, you may want to choose a sports drink thatreplaces salt and electrolytes.

How should you treat heatstroke?

The CDC recommends calling 911 immediately. Heatstroke is a medical emergency that can cause death or damage to your brain or other internal organs. After calling 911, take the following steps while you wait for help to arrive:

  • Move the person to a cooler place.
  • Apply cool cloths or get them into a cool bath if possible.
  • Don't give him or her anything to drink.
  • Remove any unnecessary clothing the person has on.