The Difference Between Dehydration, Heat Exhaustion and Heat Stroke

Date: Jun 21, 2022


One of the most important things you can do to prevent heat illness is staying hydrated. Without the right amount of fluid intake, your body can’t keep its temperature at a normal, consistent level. Dehydration happens when your body lacks the proper amount of fluids and electrolytes to keep working properly.

Dehydration symptoms include:

  • Thirst
  • Less frequent urination than normal
  • Darker urine color
  • Dry skin
  • Tiredness
  • Dizziness and/or fainting
  • Headache

Signs of dehydration may be slightly different for younger individuals. In young children and infants, dehydration symptoms can include a dry mouth and tongue, crying without tears, an extended period of time (around 3 hours) without a wet diaper, high fevers, and an unusual amount of sleepiness or drowsiness.

Heat Exhaustion

Heat exhaustion is a serious condition. Heat exhaustion happens when the body loses a great deal of water and salt (which is usually caused by profuse sweating). Cases of heat exhaustion are made much worse whenever there is a high level of humidity or physical activity involved. Notably, heat exhaustion can cause any pre-existing conditions to worsen or become more apparent. It is important to know the signs of heat exhaustion, as it could take place within a very short period of time.

Heat exhaustion signs and symptoms include:

  • Muscle cramping
  • Fatigue
  • Headache
  • Nausea and/or vomiting
  • Dizziness and/or fainting

Someone with heat exhaustion may have cool or even slightly wet skin, which indicates the body is still working toward cooling itself; however, the individual will likely have a fast and faint pulse and exhibit quick and shallow breathing.

Heat Stroke

Heat exhaustion left untreated may result in heat stroke. This is a life-threatening condition that can result in damage to the brain or other important organs. In some cases, heat stroke may cause multiple organ systems to fail and can ultimately cause death. During heat stroke, the body’s core temperature rises above 106° F within a time frame of 10 to 15 minutes. This rapid increase in body heat coupled with a failing sweating mechanism leaves the body without the ability to cool itself.

Heat stroke symptoms include:

  • Confusion
  • Altered mental state
  • Slurred speech
  • Unconsciousness
  • Hot, dry skin or extreme sweating
  • Seizure
  • Extremely high blood pressure


If you find you are experiencing any of the symptoms from a condition listed above, follow these tips:

Dehydration – The only effective method of treating dehydration is to replace lost fluids and electrolytes.

Heat Exhaustion – Remove all unnecessary clothing, including socks and shoes. The individual should take frequent sips of cool water, making sure not to take in too large a quantity too quickly as it may induce vomiting, which would further dehydrate.

Heat Stroke – Make sure someone is with the person at all times until medical services arrive, and ensure that the person experiencing the heat stroke is moved into a cooler, shaded area. Placing cold, wet cloths or ice wrapped in cloths on the individual’s head, neck, armpits, or groin may help as well.

Getting the right care at the right time and place depends on the kind of symptoms you’re experiencing — and their severity.

For milder symptoms, or if you’re not sure which kind of care you need, start with your primary care physician (PCP). Because your PCP knows your complete health history and how you respond to medication, he or she can develop the best course of treatment. If your symptoms warrant more advanced treatment, they can guide you to the right care facility.

Know Where to Go

Knowing where to go when you’re ill makes a big difference. But it can get confusing. Know where to go to get the right care at the right time. Your primary care doctor knows your medical history best, but the Emory Healthcare Network includes more than 3,450 physicians in over 70 specialties, 425 locations and 11 hospitals, as well as primary care offices, urgent cares, MinuteClinics, and 6 ERs throughout metro Atlanta. Get the care you need wherever you need it. See our map to find the locations closest to you.

Talk to Our Nurses

If you’re not sure if a trip to the ER is needed, call your family doctor or Emory HealthConnection, where our representatives or registered nurses can help you find a location or specialist that’s right for you. Call 404-778-7777: Monday – Friday, from 8 a.m. to 8 p.m. EST, Saturday from 8 a.m. – 5 p.m., and Sunday from 10 a.m. – 3 p.m.

Schedule your appointment today.

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