What are the signs of heat stroke?

July 14, 2023 Swedish Health Team

 [4 MIN READ] 

In this article: 

  • When temperatures rise, we need to be vigilant about dehydration, heat exhaustion and heat stroke.

  • Heat stroke is the most serious form of heat injury and occurs when the body's temperature rises above 103 degrees Fahrenheit.

  • A Swedish sports doctor provides guidance about what to do if someone experiences heat stroke and how to prevent it

While summer weather brings plenty of opportunities for outdoor fun and enjoyment, we also need to exercise caution when the mercury rises. In addition to sun protection for our skin, we should be vigilant about heat exhaustion, dehydration and heat stroke. Ronan Cahill, M.D., a Swedish sports doctor, shared some insights about heat stroke and what to do if we or someone we’re with is showing symptoms of this dangerous condition. 

What is heat stroke? 

Heat stroke is a condition caused by your body overheating, often as a result of prolonged exposure to or physical exertion during high temperatures. Heat stroke is the most serious form of heat injury; this occurs when your body temperature rises to 103 degrees Fahrenheit or higher. Heat stroke and other heat-related conditions, such as heat exhaustion, are most common during the summer months. But they can also occur during other times of year if we travel to a warmer climate to which we are not acclimated and exert ourselves. 

What are the symptoms of heat stroke? 

According to the Centers for Disease Control and Prevention, the symptoms of heat stroke include a high body temperature of 103 F (or 39.5 C) or higher; hot, red, dry or damp skin; a fast and strong pulse; a headache; dizziness; nausea; confusion and passing out. A compromised ability to make decisions is also a sign of heat stroke; confusion, lack of coordination and slurred speech are common indicators of heat stroke. 

What should I do if I’m with someone exhibiting symptoms of heat stroke?

Get the person into shade or somewhere cool. Make sure they drink plenty of chilled water, and if possible cool them down with a water bath or spray water. Cool, damp towels and fans or air conditioning are also very helpful. A change in demeanor can signal that someone needs assistance right away. If it is clear that the person is not acting like themselves or is obviously confused, get them to an emergency department immediately.  
How can we prevent or avoid heat stroke and heat exhaustion? 
  • Timing. Make sure to avoid being out or exerting yourself during the hottest period of the day, typically from about 12 to 4 p.m.  
  • Hydration. Drink plenty of fluids before, during and after any activity. You can gauge your hydration by the color of your urine — clear or very light yellow represents good hydration. Anything darker means that your hydration is lacking. 
  • Acclimation. Get yourself used to temperature changes. The highest risks come at the start of hot weather. You should not simply go from cold weather routines to completing the same workouts in heat. Rather, shorten your workout; slowly start to build and soon you can be back to your regular routine with less risk. 
  • Humidity. Keep an eye on the barometer. Our summers are often quite dry, but we do get some humid days..  A humid day will feel much hotter than a dry one and make you reach your limit a bit sooner. 

What other safety tips should we keep in mind during warmer weather? 

  • Wear breathable sun-protection! Avoid heavy cotton, non-breathable nylon and go with some of the great new materials that are light, breathable and offer good sun protection. 
  • Be sure to have a light hat and a good pair of sunglasses on hand to protect your face and eyes, especially.
  • Don’t forget the sunscreen! Anything with an SPF of 30 or more is great and make sure to reapply frequently (every one to two hours) if you are sweating or out on the water. We wait all winter for this glorious but short summer stretch. We want to be safe and healthy to enjoy as many of our precious summer moments as possible. 


Learn more and find a doctor

If you have questions about heat stroke, contact Primary Care at Swedish. We can accommodate both in-person and virtual visits.

Whether you require an in-person visit or want to consult a doctor virtually, you have options. Swedish Virtual Care connects you face-to-face with a nurse practitioner who can review your symptoms, provide instruction and follow up as needed. If you need to find a doctor, you can use our provider directory.

Join our Patient and Family Advisory Council.

Additional resources 

Drink up! Proper hydration is essential for good health

Fun in the sun? Remember to protect your skin!

Tips for where and how to treat common summertime injuries and illnesses

Stay safe while exercising in summer heat: Tips from a Swedish sports doc

Water sport safety

This information is not intended as a substitute for professional medical care. Always follow your health care professional's instructions.

Follow us on FacebookInstagram and Twitter

Previous Article
This summer, reduce your sodium intake with small changes
This summer, reduce your sodium intake with small changes

Making small changes to your food choices and cooking habits can make a big difference in your health.

Next Article
Staying safe and healthy during wildfire season
Staying safe and healthy during wildfire season

Swedish experts share advice to help us stay safe and healthy during smoky season. Watch the video for five...