Staying Safe in the Heat: Understanding the Difference Between Heat Exhaustion and Heat Stroke
By Orthopedic Surgeon Dr. James Slauterbeck
When the weather gets hot, it’s fun to be outside, but it’s also important to stay safe. Too much heat can make you very sick. Two of the most serious heat-related illnesses are heat exhaustion and heat stroke. Knowing the difference between them can help save lives.
What Is Heat Exhaustion?
Heat exhaustion happens when your body gets too hot and starts to lose water and salt from heavy sweating. This often occurs during sports, hard work, or long hours outside in the heat. It is serious but not usually life-threatening if identified and treated quickly.
A person with heat exhaustion will usually have a body temperature that is higher than normal, but still below 104°F (40°C). They may feel dizzy, tired, or weak. Some common symptoms include a headache, nausea, and muscle cramps. The person may sweat heavily, and their skin may be cool, pale, or clammy. Their pulse may feel fast but weak. Some people may faint or feel like they’re going to pass out, and their walking may be unsteady.
Even though they may feel confused or lightheaded for a moment, their mental status stays normal. That means they can talk clearly and answer questions, even if they feel sick. This is one of the biggest differences between heat exhaustion and heat stroke.
If someone has these symptoms, move them to a cool place right away. Help them lie down and rest. Give them water or a sports drink, and use fans, cool cloths, or shade to lower their body temperature. Most people get better within 30 minutes if they are treated quickly.
What Is Heat Stroke?
Heat stroke is much more serious, and it can be deadly if not treated immediately. It happens when the body temperature rises above 104°F (40°C) and the brain begins to shut down. This is a medical emergency, and one should immediately call 911.
Heat stroke can cause major changes in how someone acts. A person may become confused, start talking strangely, act aggressively or angry, or even have seizures. They may faint, pass out, or go into a coma. Their behavior may seem very strange, and they may not know where they are or what is happening. This change in mental status is a key sign that someone has heat stroke, not just heat exhaustion.
Their skin may feel hot and dry if it’s classic heat stroke (which usually happens in older people during extreme heat). But in exertional heat stroke (which happens more in athletes), the person may still sweat some or may feel damp from the clothes retaining sweat they are working out in. They may also have a very fast heartbeat, nausea, vomiting, and slurred speech.
Key Differences: Heat Exhaustion vs. Heat Stroke
It’s important to know the main differences between heat exhaustion and heat stroke. In heat exhaustion, the person sweats, has cool or clammy skin, and usually has a normal mental state, even if they feel dizzy. In heat stroke, the body temperature is much higher, and the person may act confused, pass out, or have seizures. Mental changes like confusion or strange behavior are the biggest warning signs of heat stroke and mean you need emergency help right away.
How Are Heat Stroke and Severe Heat Exhaustion Treated?
When heat stroke or a severe case of heat exhaustion happens, the body must be cooled down as fast as possible. This is called rapid cooling, and it can save a life. The best and most effective way to cool someone quickly is to place them in an ice bath. If that is not available, you can also place ice packs on the groin, armpits, and chest, which are areas where blood flows close to the skin. This helps cool the body faster. Time is critical and cooling should begin while waiting for emergency help to arrive.
Prevention: How to Stay Safe
The best way to stay safe is to avoid getting overheated in the first place. Drink plenty of water, wear light and loose clothing, and take breaks in the shade. Try to avoid the hottest part of the day, usually between 11 a.m. and 4 p.m., and rest often if you are working or exercising outside.
What Is Wet Bulb Testing?
One way schools and sports teams keep people safe in the heat is by using Wet Bulb Globe Temperature testing, or WBGT. This special tool looks at temperature, humidity, wind, and sun to measure how hot it really feels. It helps coaches and staff decide whether it’s safe to practice or play sports outside.
In general, in the south for high school sports, when the WBGT is under 82 degrees, outdoor activity is usually safe. Between 82 and 86.9 degrees, student athletes should receive water breaks every 15 to 20 minutes and watch closely for heat illness. When the WBGT is between 87 and 89.9 degrees, practice must be limited to one hour and may require removing pads and helmets. At 90 degrees or higher, all outdoor athletic activity should be canceled or moved indoors and carefully monitored.
Best Time to Exercise
To stay safest, exercise early in the morning before 10 a.m. or in the evening after 6 p.m., when the sun is lower and the temperature is cooler. Avoid exercising in the middle of the day when the risk of heat illness is the highest.
Final Thought
Heat exhaustion and heat stroke are not the same. Heat exhaustion is serious but can usually be treated with rest, water, and cooling down. Heat stroke is a life-threatening emergency that needs immediate medical care. The biggest clue that someone may have heat stroke is a change in their mental state, like confusion, slurred speech, or passing out.
Both heat stroke needs rapid cooling to protect the brain and body. Ice baths are best, but if that’s not possible, using ice on the groin, armpits, and chest can help. Wet bulb testing and smart choices about when and how to be active outside can help prevent these emergencies. Stay cool, stay alert, and enjoy the summer safely.
James Slauterbeck, MD, is an orthopedic surgeon whose special interests include sports medicine, adolescent sports medicine, female sports medicine, and high school and college athletic injuries. He is affiliated with UNC Health Orthopedics at Southeastern Health Park and UNC Health Southeastern. To learn more, call (910) 738-1065 or visit https://www.unchealth.org/care-services/doctors/s/james-r-slauterbeck-md.
