Heat Stroke vs Heat Exhaustion 

In hot months, we often love to get outside to play or work. With this comes the risk of heat related illnesses. There is always the question whether someone may have heat stroke vs. heat exhaustion. Both happen when the body can’t cool itself. Normally, the body releases sweat that evaporates to cool the body. If the weather is too hot and too humid, this process may be hampered and your body may not cool fast enough. This causes heat related illness that can be very serious. Heat exhaustion and heat stroke are medical emergencies and should be treated right away. Read on to learn more about the signs, symptoms and what to do.

Definitions of Heat Stroke vs Heat Exhaustion

Heat Exhaustion This is when your body has been exposed to excessive heat without taking measures to keep cool. Your body sweats too much and dehydrates you.

Heat Stroke This often happens if heat exhaustion is left untreated. It can also happen if your body becomes too overheated to cool itself down. In this case, your body temperature can go as high as 104°F. Left untreated, it can cause internal damage, serious illness and even death.

Causes of Heat Stroke & Heat Exhaustion

Heat exhaustion and heat stroke are both caused by excessive heat. Sometimes it isn’t possible to stay completely out of the heat, but there are factors that complicate it and impair the body’s ability to cool, including:

  • Extremely hot days with high level of humidity
  • You are already suffering from other diseases like vomiting, fever, and diarrhea
  • Lack of air conditioning or fans in the room
  • Using alcohol or drugs (alcohol dehydrates and drugs can shut down ability to sweat)
  • Inability to be inside an air-conditioned building i.e. working outside, waiting for a ride, etc.
  • Dressing too warm
  • Elderly people (As skin ages , it loses the ability to respond to heat)

Risk Factors for Heat Stroke

Even if you are well prepared for hot days, there are a few things that may complicate your exposure to heat. Use extra caution if the following apply to you:

Medication Use. There are certain medications that will impair your response to heat and dehydration. Use extra caution if you take the following medications: diuretics (medications that cause you to lose fluids), anti-depressants (can impair sweat response), vasoconstrictors (closes up the blood vessels), blood pressure medications (blocks adrenaline), stimulants that treat ADHD and illegal stimulant drugs (shuts down nervous system response for cooling).

Medical Conditions. The following medical conditions can put you at higher risk for heat stroke; kidney disease, heart disease, lung disease, obesity, previous heatstroke, and an inactive lifestyle.

Symptoms of Heat Stroke vs Heat Exhaustion

Figuring out if you have heat exhaustion or heat stroke can be tricky. The table below outlines the differences in the symptoms of each:



Heat Exhaustion

  • Severe Thirst
  • Dark Urine Color
  • Feeling Dizzy
  • Slow/Weak Heartbeat
  • Extreme Sweating
  • Clammy Cool Skin

Heat Stroke

  • Fast Heartbeat
  • High Body Temp

(104°F and up)

  • Lack of Sweat
  • Hot, Dry Skin
  • Delirious, Confused

(Possibly Unconscious)

  • Shortness of Breath
  • Unable to Urinate

Similar Symptoms in Both

  • Nausea/Vomiting
  • Muscle Cramping
  • Seizures
  • Headache
  • Fatigue
  • Dizziness

How to Deal with Heat Stroke & Heat Exhaustion

Whether you have heat exhaustion or heat stroke, both need to be treated right away. Here are the treatments for both:

Heat Exhaustion

If you notice that you or someone you know is suffering from the symptoms above, do the following quickly:

  • Immediately bring fluids. A sports rehydration type drink is best, but any fluids you have on hand is better than none. Constant fluid intake is necessary for the next 2 or 3 hours. Do Not Use Caffeinated Drinks or Alcohol, which can cause dehydration.
  • Get indoors or in the shade. Going inside into a cool house is best, but if you’re not near a building, get out of direct sun.
  • Loosen clothes and apply a cool wet cloth. Take off as much clothing as possible and wipe down with a cool wet cloth. Make sure the water is not too cold which can cause shivering and further constrict blood vessels, making the condition worse.

A warning is that you should see your doctor soon if you do not feel better in 30 minutes. If heat exhaustion is not treated immediately, it can turn to heat stroke.

Heat Stroke

Heat stroke is a very serious medical emergency. If you or someone you know has the symptoms of heat stroke, call 911 right away. You need to do the following while you are waiting for emergency medical help:

  • Give fluids if they are conscious. Only give them something to drink if they are awake and talking to you. Never give them any medications for fever if you suspect heat stroke.
  • Get them inside right away. Get inside to a cooler place and turn on air conditioners and/or fans to get the air moving.
  • Place cool cloths. Never cold, but cool cloths can help lower skin temperature. Do not completely immerse them in water as this can make them sicker.
  • Massage the skin. Give them a gentle massage to help increase blood flow.
  • Place in recovery position. If they are unconscious, place them on the left side in case they vomit. Keep objects away if they are having a seizure.

When to See a Doctor

If you are experiencing symptoms of heat stroke or heat exhaustion, call 911 right away. Better to have a medical professional evaluate and decide which you have. These groups need immediate medical attention regardless of the symptoms:

  • Small children less than two years old
  • Elderly adults
  • People with underlying medical conditions like: diabetes on insulin, kidney disease, heart disease, or issues with blood circulation

How to Prevent Heat Stroke & Heat Exhaustion

Keep an eye on the weather. Know the triggers for heat exhaustion and heat stroke and avoid them if you can. If you must go out in hot weather, take these precautions:

  • Drink water before going out in the heat and during exposure.
  • Stay out of closed up spaces such as cars, sheds, and other areas with little or no ventilation. Never leave children and pets in a car.
  • Avoid alcohol or caffeinated drinks.
  • If you have symptoms of heat exhaustion in the sun, move to the shade. Take immediate steps to cool your body.
  • Stay inside during the hot period of the day: 11 a.m. to 4 p.m.
  • Avoid exercise or strenuous activities in extreme heat.
  • Wear light clothing.
  • Use a sunshade or an umbrella. Hats always help to keep the head and face cool.
  • If you do not have air conditioning, open windows and use fans.

The video below will give you a vivid presentation of the differences between heat stroke and heat exhaustion, how to treat them and prevent them: