Know the difference between heat exhaustion and heat stroke

Though closely related and sharing many symptoms, heat exhaustion and heat stroke are not to be treated equally. Knowing the difference between these two heat related illnesses could save a life. 

Heat exhaustion

Heat exhaustion is caused when the body overheats due to prolonged exposure to high temperatures, especially when combined with high humidity and physical activity. This can happen to anyone whether working outdoors at a jobsite, gardening, playing sports or while simply enjoying the summer sun.

Signs of heat exhaustion

Heat exhaustion can creep up on you. Once symptoms start, it’s important to take care of them before they progress to heat stroke.  Signs of heat exhaustion include:

• Excessive sweating and/or pale, clammy skin. Sweat is one of the ways the body cools its temperature. 
• Elevated body temperature. A body temperature of 100.4° to 103° F can indicate heat exhaustion. 
• Dizziness and/or fainting.
• Nausea or vomiting.
• Muscle weakness or heat cramps. Heat exhaustion and dehydration can affect muscles. 
• Changing vital signs. A fast heart rate, weakened pulse, and rapid breathing are all signs of heat exhaustion.

How to treat heat exhaustion

Often, once someone starts experiencing signs of heat exhaustion, quick action is needed to keep their condition from deteriorating to a more serious, and sometimes deadly, heat related illness - heat stroke. 

• First, aim to cool down and rehydrate the individual.
• Move to air conditioning or a shady spot and use cold compresses or water to cool down skin.
• Administer cool fluids like water or sports drinks to help restore hydration and avoid caffeine or alcohol.
• Loosen clothing or remove any heaving clothing.
• Lay the individual down and elevate feet if they’re feeling dizzy or faint.

While recovering from heat exhaustion, make sure to avoid excessive heat and strenuous activities and get plenty of rest. If symptoms worsen or last more than an hour, or if the person becomes confused or loses consciousness, it maybe progressing to heat stroke.  

Heat stroke

Heat stroke, medically known as severe hyperthermia, occurs when your body loses the ability to cool itself down with traditional methods like sweating. Untreated, heat stroke can cause internal organs to fail or even death. Though it can happen quickly without warning signs, knowing symptoms can help keep you and others safe.

Signs of heat stroke

There are telltale signs that a person’s body is no longer able to regulate internal temperature. Heat stroke can often start out with the symptoms of heat exhaustion, but unlike heat exhaustion, heat stroke requires immediate medical attention. Watch for these signs of heat stroke:

• Dry hot skin. One of the main symptoms differentiating heat stroke is the lack of sweating, as the body can no longer adequately cool itself with sweat. Note that skin can be moist if the heat stroke is caused by exertion, such as manual labor or outdoor sports.
• Body temperature.  A body temperature of 104° F or higher is dangerous to internal organs. 
• Behavioral differences. Heat stroke can cause increased aggression or irritability.  
• Neurological differences. Confusion, headache, slurred speech, seizures, dizziness or lightheadedness, and unconsciousness are all important indicators.
• Deteriorating vital signs. Rapid breathing and increased heart rate or excessive pulse strength should not be ignored.  

How to treat heat stroke

Heat stroke is a medical emergency. Immediately call 9-1-1. While waiting for emergency medical care, a few things can be done to keep the individual safe until help arrives:

• Get out of the heat and sun. Move to an air-conditioned location or get into a shady spot.
• Cool the body. You can do this by removing layers or by placing cold compresses in the neck, armpits and groin. Immerse the individual’s body in cold water if possible or use fans and spray water on their skin.
• Do not administer fluids if the person is unconscious or confused. When help arrives, medical professionals will make sure the right amount is given at the right time and in the right way, which may be though an IV. 

Heat exhaustion vs heat stroke 

Knowing the difference between heat exhaustion and heat stroke could save a life. Though the illnesses share some similarities, some symptoms can help tell them apart. 

How to prevent heat exhaustion and heat stroke

Preventing heat-related illnesses starts with being proactive. Make sure to plan ahead if you will be in the heat or sun for an extended period. 

• Stay hydrated. Drink plenty of fluids before, during and after spending time in the heat. Staying hydrated will help regulate your body temperature via sweating, as well as replace what you lose with sweat. Add in electrolytes, like sports drinks, to support mineral levels in your body. Avoid alcohol, caffeine and sugary beverages.
• Limit time in the heat and rest often. Try to avoid physical activity during the hottest parts of the day. Move exercise indoors during excessive heat, if possible. If you’re unable to avoid the sun and heat, take frequent breaks in the shade or air conditioning to keep your body cool. 
• Dress accordingly. Your clothing should be loose and light, like athletic material or breathable cotton. Wear light colors and dress in layers so you can remove clothing to cool off when necessary.
• Watch the weather. Before heading out in the heat, check your forecast and National Weather Service HeatRisk map. Knowing the weather can help you prepare accordingly with sunscreen, shade, clothing, hydration and more. 

Risk factors for heat stroke and heat exhaustion

Many variables can impact how soon heat exhaustion can start, including humidity, physical activity and your body’s current state of hydration. Some individuals may be more at risk of developing a heat related illness like heat exhaustion or heat stroke due to their lifestyle or health conditions.

Those with heightened risk include:

• Individuals 65+ or children younger than 4, whose bodies have a harder time self-regulating temperature. 
• Those who work outdoors, especially workers who need to wear heavy protective equipment.
• Individuals who participate in outdoor exercise or sports. 
• People with certain health conditions including heart disease, obesity, and lung disease. 
• Certain medications can speed up dehydration and increase the risk of heat-related illness. 

If you think you might be at higher risk for heat related illness, be proactive and talk with your primary care provider.