Wellness Fitness What Is Heat Stroke? By Sarah Jividen, RN Sarah Jividen, RN Sarah Jividen, RN, BSN, is a trained neuro/trauma, and emergency room nurse turned healthcare freelance writer. As a journalism major, she combined her love for writing with her passion for high-level patient care. health's editorial guidelines Published on July 14, 2023 Medically reviewed by Michael Menna, DO Medically reviewed by Michael Menna, DO Michael Menna, DO, is currently an attending emergency medicine physician at White Plains Hospital in White Plains, New York, with nearly 10 years of experience. learn more In This Article View All In This Article Types Symptoms Causes Diagnosis Treatment Prevention Related Conditions Living With Heat Stroke FAQs Liudmila Chernetska / Getty Images During summer months and warmer temperatures, the risk of experiencing heat-related illnesses can increase. A heat stroke occurs when the body overheats and cannot control its temperature when it's exposed to high temperatures or intense physical activity in hot environments. Heat strokes are serious illnesses and can cause symptoms such as loss of consciousness, confusion, and seizures. If you do not receive treatment quickly enough, the condition can unfortunately become fatal. On average, about 702 heat-related deaths occur in the United States each year. That's why recognizing the signs and symptoms of heat stroke, knowing when to seek care from a provider, and taking preventive measures can make all the difference. Types of Heat Stroke There are two primary types of heat stroke, which include: Classic heat stroke: This occurs when you are exposed to extremely hot conditions, such as heat waves. Exertional heat stroke: This happens when you perform vigorous physical activity and overheat during exercise. Symptoms Knowing the symptoms of heat stroke can help you or someone else get the support they need to save their life. Be on the lookout for the following symptoms: A body temperature of 103 degrees Fahrenheit or above Confusion or disorientation Loss of consciousness Hot and dry skin that appears red A rapid pulse Heavy breathing Pounding headache Feeling dizzy or lightheaded Nausea or vomiting Weakness Fatigue Low blood pressure Keep in mind: these symptoms can vary depending on the type of heat stroke you have. With classic heat stroke, the skin may appear more hot and dry, while exertional heat stroke can cause prolonged sweating occurs after exercise stops. If you experience heat stroke symptoms or notice someone else that may be displaying signs of a heat stroke, it's essential to seek out medical care as soon as possible. Causes Heat stroke can happen when your body's core temperature rises. This can occur due to prolonged (long-term) exposure to high temperatures or performing intense physical activity in hot environments. If you have heat stroke, your body temperature can escalate rapidly, reaching 106 degrees Fahrenheit or higher within a matter of minutes. When this happens, your body isn't able to cool itself down and fails to regulate temperature properly, leading to heat stroke symptoms. Risk Factors Other risk factors that can make you more vulnerable to developing heat-related illnesses include: Not drinking enough water Consuming excess alcohol, which can lead to dehydration Having a history of previous heat illness Taking prescription medications that affect the body's ability to retain water or respond to heat Diagnosis If you or someone else is experiencing heat stroke symptoms, it's important to call for medical help as soon as possible. A healthcare provider can diagnose you with heat stroke by completing the following steps: Taking a full medical history about your symptoms, recent exposure to hot temperatures, exercise habits, and underlying medical conditions Performing a physical exam and measuring your vital signs, such as your body temperature, heart rate, blood pressure, and respiratory rate Using a rectal thermometer to get an accurate reading of your body's core temperature Ordering blood tests to assess your electrolyte levels, kidney function, liver enzymes, blood glucose (sugar), and other tests to help identify any organ dysfunction or complications associated with heat stroke Treatment Heat stroke is a medical emergency that requires immediate treatment. You should call 911 or visit your local emergency room as soon as possible. The primary goals of treatment for heat stroke are to lower the body temperature, prevent organ damage, and stabilize your vital signs. This can be done by using the following treatment methods: Moving to a cool environment to reduce exposure to the source of heat Remove excess clothing to maximize heat loss from your body Rapidly cool your body temperature by getting into a cold tub or using wet towels Applying ice packs or cold compresses to the neck, armpits, groin, and back to help your body cool down quicker Rehydrating you with water Depending on the severity of your condition, your healthcare provider may also recommend the following techniques when you are at the hospital: Taking an ice bath Being hooked up to an intravenous (IV) infusion to help give your body the fluids it needs Using a cooling blanket How to Prevent Heat Stroke It is essential to take preventive measures to avoid heat stroke, especially during hotter seasons or when engaging in physical activity. The following tips may help prevent heat stroke: Drinking enough water before you feel thirsty Avoiding excessive consumption of alcohol Wearing loose-fitting, lightweight, and light-colored clothing in the summer Staying in the shade or in air conditioning as much as possible Scheduling your activities during cooler times of the day Taking breaks and rest on hot days Using a wide-brimmed hat or umbrella to shield yourself from direct sunlight Applying a broad-spectrum sunscreen with a high sun protection factor (SPF) Minimizing intense physical activity during hot or humid weather conditions It is also a good idea to keep an eye on infants, young children, older adults, and those with chronic illnesses, as they are more susceptible to experiencing heat-related illnesses. Related Conditions Heat stroke is the most serious of all heat-related illnesses. However, there are other types of heat-related illnesses to be aware of, including: Rhabdomyolysis: A condition that causes the breakdown of skeletal muscle tissue, which can occur as a result of extreme physical exertion in hot environments. If left untreated, the condition can cause kidney damage. With this condition, you may experience muscle pain or weakness, dark colored urine, excessive fatigue, and swelling or stiffness in the muscles. Heat Syncope: A temporary loss of consciousness, fainting, and dizziness due to inadequate blood flow to the brain. This typically happens after you are standing too long or are exposed to high temperatures. If you suspect that you or a loved one may have symptoms of these conditions, seeking medical attention for proper diagnosis and treatment is essential. Living With Heat Stroke The Centers for Disease Control and Prevention estimate that more than 60,000 people visit the emergency room for a heat-related illness each year. More than 13% of these people need to be hospitalized because of their condition. Unfortunately, an average of 700 people die due to heat stroke each year. Your prognosis (or, outlook) for heat stroke will depend on a variety of factors, including your age, underlying conditions, how high your temperature rose, and how quickly you sought treatment from a healthcare provider. As a rule of thumb, taking preventative measures on hot days and removing yourself from hot conditions as soon as possible can improve your chance of survival. The longer you wait without receiving care, the more serious your condition can become. It's important to note that once you recover from heat stroke, you should take rest and avoid physical activity and hot conditions for at least one week. Your healthcare provider should provide guidance on what you can and cannot do during your recovery. Once you experience heat stroke, you are also at an increased risk of experiencing another heat-related illness. That said, your provider may recommend regular check-ups and prevention strategies to reduce your risk. Frequently Asked Questions What is the difference between heatstroke and heat exhaustion? Heat stroke is a severe condition that occurs due to prolonged exposure to high temperatures. The body isn't able to control its temperature and this condition can become life-threatening. On the other hand, heat exhaustion is a milder form of heat-related illness that leads to heavy sweating, weakness, and dizziness and is usually caused by dehydration and inadequate fluid intake in hot environments. How long after sun exposure does heat stroke occur? Heat stroke can occur relatively quickly after sun exposure, particularly in extreme heat conditions. In some cases, it can develop within as little as 10 to 15 minutes of exposure to very high temperatures. Is heat stroke an emergency? Yes, heat stroke is a medical emergency that requires immediate attention. It is a life-threatening condition that can lead to organ damage or even death if not treated promptly and effectively. Was this page helpful? Thanks for your feedback! Tell us why! Other Submit 11 Sources Health.com uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy. Centers for Disease Control and Prevention. Heat stress – heat related illness. Centers for Disease Control and Prevention. Heat and health tracker. Morris A, Patel G. Heat Stroke. In: StatPearls. StatPearls Publishing; 2023. Bouchama, A., Abuyassin, B., Lehe, C. et al. Classic and exertional heatstroke. Nat Rev Dis Primers 8, 8 (2022). https://doi.org/10.1038/s41572-021-00334-6 Centers for Disease Control and Prevention. Warning Signs and Symptoms of Heat-Related Illness. Centers for Disease Control and Prevention. Frequently asked questions about extreme heat. National Weather Service. Heat Cramps, Exhaustion, Stroke. Leiva DF, Church B. Heat Illness. In: StatPearls. StatPearls Publishing; 2023. Centers for Disease Control and Prevention. Tips for preventing heat-related illness. Medline Plus. Rhabdomyolysis. Medline Plus. Heat illness.