Heat Exhaustion and Heat Stroke Symptoms

Heat exhaustion can occur if the body has a hard time cooling down. This reaction is usually the result of dehydration and salt depletion. If you experience heat exhaustion, you'll likely be sensitive to heat for up to one week after symptoms.

Symptoms start mildly and gradually develop over time. Heat cramps, fatigue, heavy sweating, and thirst are often the first signs of heat exhaustion. Heat stroke can occur if the body temperature rises to more than 106 degrees, which can be fatal if untreated. Signs of heat stroke and heat exhaustion include dark urine, dizziness, headache, nausea, and rapid breathing or pulse.

First aid includes getting to a cool, shaded area right away and sipping an electrolyte solution. Call 911 right away if a person develops heat stroke symptoms. Read on to learn about heat exhaustion and heat stroke, including signs, prevention, and more.

Heat Exhaustion vs. Heat Stroke

You can develop heat exhaustion when your body has to work extra hard to cool you down. The body's temperature is usually less than 104 degrees, blood pressure is low, and the heart is not pumping blood efficiently during heat exhaustion.

The body, however, is still functioning normally at this stage. You'll likely feel very fatigued, sweat a lot, and be thirsty, so these natural defenses against heat and dehydration are still working.

Heat exhaustion does not necessarily lead to heat stroke, but it could. Exertional heat stroke usually occurs when the body's temperature rises above 106 degrees. This causes your body to lose its ability to thermoregulate.

Heat stroke causes the central nervous system to malfunction. This life-threatening health concern can also damage the brain, heart, liver, kidneys, spleen, and muscular tissue.

Heat Syncope

Heat syncope, or fainting, can occur if you stand in hot temperatures for too long. You might feel dizzy if you suddenly stand after sitting or lying down. Being dehydrated or not acclimated to the weather can increase the risk of fainting.

Symptoms

Heat cramps are often the first sign of heat illness. You might experience muscle pain or spasms, typically in the abdomen, arms, or legs.

Heavy sweating is another sign that your body is producing a lot of heat. Heat is more dangerous on humid days because sweat cannot evaporate off the skin, which normally produces a cooling sensation.

Other early signs of heat exhaustion include fatigue and thirst. Light, straw-yellow urine is typically a sign you are hydrating well. Dark and concentrated urine, in contrast, means you are not well hydrated. This can indicate you are not able to release heat as efficiently through sweat and evaporation, which puts you at risk of overheating.

Signs of Heat Exhaustion and Heat Stroke

Heat illness can progress to heat exhaustion if conditions do not improve or worsen. Later signs of heat exhaustion include:

• Cool, moist skin
• Dark urine
• Dizziness or lightheadedness
• Headache
• Nausea or vomiting
• Pale skin, which may appear ashen or grey in people with darker skin
• Rapid breathing or pulse
• Weakness

You might develop heat stroke if your body temperature increases to dangerous levels. Heat stroke may cause confusion, loss of consciousness, seizures, and slurred speech. This heat emergency can be fatal if untreated.

Other Symptoms

The first signs of a heat illness are often stomach cramps or nausea, which can indicate dehydration or an electrolyte imbalance. The body needs water and electrolytes like sodium to regulate its temperature properly, but it loses them through sweat.

Heat exhaustion often makes people dizzy, need to sit down, or even pass out momentarily. A rapid heart rate and syncope may accompany dizziness. Heavy sweating may irritate your skin, resulting in a heat rash.

Treatment and First Aid

Stop what you are doing right away if you feel like you are going to overheat. Any significant deterioration in performance or signs of struggling are reasons to take a break.

One of the most important things you can do for yourself or someone else experiencing heat illness is to get out of the sun. Get to an air-conditioned area if possible, but anywhere with shade can help. A location bathed in direct sunlight can have a heat index value up to 15 degrees higher than a spot nearby in the shade.

Here's what to do once you find a good place to cool down:

• Drink water or a sports drink that contains electrolytes: You can also make your own electrolyte solution by mixing a teaspoon of salt per quart of water. This will help replenish the sodium lost through sweat. Sip until you are feeling better.
• Improve air circulation: The body cools down through convection. This is the process of air or water flowing across the skin and transferring away heat. You can help this process by increasing air circulation and the air's exposure to the skin. Loosen clothing, make sure nothing's too tight, or remove items. Using a fan, manual or electric, can also help lose excess body heat.
• Sit or lay down: Heat illness can compromise blood flow. Sit or lay down with your feet elevated about 12 inches to prevent swelling in the legs and improve blood flow to the brain. Sitting or lying down can also protect you from falling and injuring yourself if you feel faint.
• Try an ice bath: If your body temperature has reached dangerous levels, a full-body immersion in an ice bath or a cold body of water can quickly lower it. 
• Use cold water or ice to cool down: Do not place ice directly on the skin. Spritzing yourself with water can mimic sweating and help you evaporate some of the heat off of your body. The groin and armpits are especially effective spots for cooling. The palms of the hands, feet pads, and the forehead can also be helpful.

When To Contact a Healthcare Provider

Get medical attention right away if a person shows signs of heat stroke. It's important for a healthcare provider to closely monitor their blood pressure, temperature, heart and respiratory rates, and central nervous system.

Call 911 if a person with heat illness symptoms has:

• A fever that's higher than 102 degrees
• An altered mental state
• Loss of consciousness for any amount of time
• Rapid breathing or pulse
• Seizures
• Worsening symptoms

Heat exhaustion may not need medical attention. A person will probably be fine after cooling down and resting if they are young, healthy, and thinking clearly. Older adults and those with health conditions like diabetes and heart disease might need to see a healthcare provider.

Prevention

Heat stroke can be dangerous, even fatal, and difficult to treat once it sets in. That's why it's important to prevent it from happening in the first place. 

Here are some ways to prevent heat exhaustion and heat stroke:

• Allow cars to cool down before driving. Never leave a child or pet in a hot car.
• Avoid physical activity in hot or humid weather
• Be careful spending time outdoors in hot temperatures if you take medications that increase the risk of overheating
• Drink plenty of fluids, especially before and after exercise
• Seek shade if possible
• Take frequent rests
• Wear lightweight, loose clothing that's lightly colored

Do not jump right back into activity in the hot sun after a heat-illness scare. You may still be dehydrated or at risk for rapidly overheating if you go at it again. Take the rest of the day off from physical exertion, even if your symptoms go away and you feel better. 

A Quick Review

Heat cramps are usually the first signs of heat illness, which can progress to heat exhaustion. Heat exhaustion is when your body has difficulty cooling down. Treatments for heat exhaustion include applying a cool compress, lying down in a cool area, and sipping a drink with electrolytes in it.

However, severe symptoms, such as confusion, loss of consciousness, and slurred speech, are signs of heat stroke. This severe complication can be fatal if untreated. Call 911 right away if a person develops heat stroke symptoms.

FAQs