Heat exhaustion occurs when your body overheats in response to external factors, like high temperature. Heat exhaustion can happen to anyone. It’s common in athletes, particularly those who exercise outdoors during extreme summer weather. It can also occur if you’re in a hot car or other indoor area that isn’t air-conditioned. Babies, small children, and older adults are more susceptible.

Heat exhaustion is less severe than heatstroke, but can lead to this more dangerous condition. Keep reading to learn more about this condition and what you can do to prevent heat exhaustion.

The symptoms of heat exhaustion can come on suddenly without warning, or they may creep up on you gradually. You may have one or several symptoms, including:

  • a drop in blood pressure when exerting yourself, such as moving from a sitting to a standing position, which can make you feel dizzy or lightheaded
  • dizziness
  • nausea
  • feeling faint or having the sense that you are going to black out
  • sweating profusely from many areas of the body
  • moist, cool, or cold skin, coupled with goose bumps, even in extreme heat
  • a pulse rate that becomes weak and rapid
  • headache
  • muscle cramping

Heat exhaustion vs. heatstroke

Heatstroke is more serious than heat exhaustion. Heat exhaustion can quickly turn into heatstroke if left untreated. Symptoms of heatstroke may include:

  • headache
  • a very high fever of 104°F (40°C) or more
  • disorientation
  • confusion
  • bright red, flushed-looking skin

Your skin may also become parched and dry, or feel moist to the touch. Your heart may start to race. Seizures and coma may also occur. Heatstroke is a medical emergency that requires immediate medical help.

Learn more: Do you have heatstroke or heat exhaustion? »


Dehydration can occur alongside heat exhaustion. If you have heat exhaustion, you may also be dehydrated.

Dehydration symptoms differ in babies, children, and adults. In babies, symptoms may include:

  • sunken soft spot, which is the soft area on the top of the head
  • crying without tears
  • sunken eyes
  • going three or more hours without urinating
  • crankiness
  • listlessness

In older children and adults, dehydration is typically identified by extreme thirst and urine that is dark in color. Fatigue, confusion, and dizziness may also occur.

Heat exhaustion can occur if your body temperature increases and you’re not able to cool yourself down quickly enough. This may happen in high temperatures, such as those experienced during the summer months. High humidity combined with high temperatures can also increase your risk for heat exhaustion. Another common cause of heat exhaustion is sitting in a hot car with no air conditioning.

Intense physical activity performed in heat and humidity is another common cause of heat exhaustion.

Dehydration can also increase your risk for heat exhaustion. That’s why it’s important to stay hydrated, especially on hot days.

You can also develop heat exhaustion if you’re in a hot environment for several days without a break in temperature. Over time, your body temperature can become too high, leading to heat exhaustion.

You’re at increased risk for heat exhaustion if you:

  • have a physical job that requires strenuous activities or wearing heavy, protective clothing in hot environments
  • participate in strenuous sports outside in the heat, like long-distance running
  • are aged 65 years or older
  • are obese
  • have a bad sunburn
  • take certain medications, such as diuretics, beta blockers, and antihistamines

If you think you’re experiencing heat exhaustion, stop what you’re doing and rest.

  • Cool your body down by moving to a shady area or to an air-conditioned spot.
  • Drink water or a beverage with electrolytes, like a sports drink, to help you rehydrate yourself. If possible, have someone else bring you a drink while you rest.
  • If you’re wearing tight, confining clothing, loosen or remove it.
  • Remove heavy clothing or accessories.
  • Apply ice packs or towels soaked in cold water to your body. Placing these on your forehead, your wrists, the back of your neck, or under your arms can be particularly effective.

With treatment, full recovery typically occurs within a couple hours. If your symptoms worsen or don’t improve, seek medical help immediately.

Once the causes of heat exhaustion have been eliminated, your symptoms should begin to improve. If your symptoms do not go away within a couple hours, or if they are getting worse or your temperature continues to climb, call your local emergency services. Heat exhaustion can quickly turn into heatstroke, which is a serious condition.

If a baby, small child, or older person has heat exhaustion symptoms, they should be seen by a medical professional, even after their symptoms improve.

When it’s hot outside, it’s important to keep cool, rested, and hydrated. If you think you have heat exhaustion, stop what you’re doing, find a cool area or a way to cool down your body, and rest. If your symptoms don’t improve with self-treatment, seek emergency medical help. It’s important to reduce your body heat to avoid heatstroke.

Learn more: Heat emergencies »

You can’t change the weather, but there are some things you can do to reduce your risk for heat exhaustion when it’s hot outside.

  • Stay in a cool place when the heat index climbs. If you don’t have air conditioning at home, find out if there’s a cooling center in your area. Public libraries, malls, and movie theaters are also usually air-conditioned and may provide some relief during the hottest parts of the day.
  • Never leave a child or baby in a hot car, even for a few minutes. Temperatures in cars can rise rapidly.
  • Wear lightweight and light-colored clothing. Dark colors attract and absorb heat, which may increase your body temperature.
  • Wear a lightweight sunhat if you’re going to be in the sun. Keeping the sun off of your head and face can help control your body temperature.
  • Wear sunscreen when in the sun to avoid sunburn.
  • Stay hydrated when it’s hot outside. Your body can become dehydrated before you notice signs. Keep a bottle of water with you and drink from it frequently.
  • When it’s hot outside, limit outdoor workouts to early morning or dusk, or consider joining a gym that has air conditioning. Swimming is also a great way to get exercise when it’s hot outside.