Know the difference between heat exhaustion, heatstroke

Heat Exhaustion, Ohio State Medical Center

During the dog days of summer, it doesn’t take long for things to heat up – and become dangerous.

Heat exhaustion and heatstroke can strike when summer’s cauldron begins to bubble. But it doesn’t take 100-degree temperatures to lead to heat sickness. It can happen when there’s a sudden rise in temperature, or when high humidity begins to accompany warm conditions.

Spotting the signs of heat illness can be critical for you or your friends and family who are spending time outdoors. Eric Adkins, MD, who works in emergency medicine, says heatstroke can be fatal if it goes unrecognized and untreated.

“People who are suffering from heatstroke often are confused, and they may not know to seek out care or remove themselves from a hot environment,” he says. “Without proper treatment and cooling, the brain will essentially overheat.”

It’s important to know the difference between heat exhaustion and the more dangerous condition of heatstroke. Here’s a summary of each, and how they’re treated:

Heat exhaustion

What is it?
  • A heat-related syndrome brought on by high temperatures
  • It might be caused by being dehydrated, consuming alcohol or wearing clothes that are too warm

  • Fatigue; nausea; headache; high body temperature; decreased sweat and urine output

  • Get out of the heat
  • Drink plenty of fluids and use cool towels to lower your body temperature
  • Take a cool bath or shower


What is it?
  • The interruption of the body’s ability to cool itself down, brought on by high temperatures

  • Elevated body temperatures of 103 degrees or more; rapid pulse rate; loss of consciousness; fever; delirium; hot, dry skin

  • Heatstroke is a medical emergency. Call 911 if you suspect that you or someone you’re with is having heatstroke. Medical specialists need to cool the patient’s body and can do so with ice baths, ice packs or catheters placed in large blood vessels. They’ll also monitor the patient’s heart rate and electrolyte levels.

Eric Adkins, MD, Ohio State Medical CenterPrevention is the key to avoiding heat illnesses.

“If you know you’re going to be outside for a long period of time, just plan for it,” Adkins says. “Make sure you have plenty of water. Make sure that you take breaks from the heat. Every hour or so, go inside and have a drink of water.

“Make sure you have adequate urine output. If you’re sweating and not drinking enough, you’ll stop making urine. Wear sunscreen and appropriate clothing.”

Adkins warns that consuming alcohol and taking certain medications, such as anti-depressants and antihistamines, can cause harm in the heat. Alcohol can dehydrate the body, and the medications may inhibit the body’s ability to sweat.

Athletes should be aware of the body’s needs before exercising when temperatures rise significantly. Pre-hydrating before exercising is essential.

It’s also wise to watch out for the warning signs of heat exhaustion and heatstroke – dizziness, weakness, lack of sweat and a listless feeling.

“The body isn’t meant to function at 108 degrees,” Adkins says. “The brain can’t tolerate that. When you get abnormal electrical activity in the brain, it can lead to seizures and other depressed activity.

“You have to find a way to cool the body down.”

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