Identify differences: Heat & dehydration - Signs & advice

Heat stroke, heat exhaustion, and dehydration commonly occur to those who spend time in the heat and may not drink enough fluids. However, it is important to know that these three are very much different in symptoms and treatment. It is critical to know which is which to know the proper and timely management of victims. While heat stroke and exhaustion are commonly heat-related, dehydration can also occur in combination with fever, diarrhea, or vomiting.

Symptom identification

Though these three exhibit some similar symptoms, they have key differences that can be noticed right away. A proper diagnosis leads to correct management. If you are the only person near the victim or the victim, you may be the only difference between safety and endangerment.

Dehydration Heat exhaustion Heat stroke
Thirst Nausea or vomiting Nausea
Dry mouth and mucous membranes Headache Headache
Light-headedness Weakness Disorientation, agitation, or confusion, hallucinations
Fatigue Muscle cramps Fatigue
Dizziness Dizziness Dizziness
Confusion Loss of consciousness Loss of consciousness/Seizures
Decreased urination Heavy sweating High body temperature (>103 °F or higher)
Dry skin Cold, pale, and clammy skin Hot, red, dry, or damp
Increased pulse and breathing Fast, weak pulse Fast, strong pulse

Proper management

If identified correctly, the correct steps can be taken to treat these conditions. For any case, always call 911 or seek emergency medical help right away if possible. Sometimes, dehydration may be caused by a more serious underlying condition requiring immediate medical attention.

Dehydration Heat exhaustion Heat stroke
Rehydration by drinking fluids or electrolyte drinks Move the victim to a cooler place Move the victim to a cooler place
For more severe cases, IV fluids may be needed Sip water Do not let the victim drink anything
  Lower the victim’s temperature Lower the victim’s temperature
    Call 911 right away

Lowering the victims temperature can be done by having them lie in a shaded area and elevate their feet, applying cool water to the skin and fanning them, or applying ice packs to the groin and armpits. Use whatever resources that you have to help them cool down.


Prevent heat exhaustion, heat stroke, and dehydration by taking good care of yourself and your loved ones.

  • Drink enough fluids when you’re out in the sun. You will need more fluids to stay hydrated when it is hot out than you typically would.
  • Schedule any physical activity during cooler periods of the day.
  • Wear a hat, sunglasses, and umbrella
  • Use sunscreen.
  • Never leave children or pets in hot cars, even for a minute.


This page was written by on Dec 7, 2020.
This page was last reviewed and updated by on Jul 18, 2023.