When temperatures reach the upper 90s and into the 100s for even a short period of time, residents need to take extra precautions with their health. Two common problems involved with extreme heat are heat exhaustion and heat stroke.


What is heat exhaustion?

Heat exhaustion or heat stress is the overheating of the body due to excessive loss of water. It can be caused by prolonged exposure to hot temperatures, limited fluid and/or insufficient dietary salt intake. Anyone can develop heat exhaustion during hot weather. Certain situations can lead to heat illness more readily; long stretches of hot days, recent illness, heavy/restrictive clothing, or working in a hot environment.


What are the warning signs of heat exhaustion

    • Heavy sweating
    • Paleness
    • Muscle cramps
    • Tiredness
    • Weakness
    • Dizziness
    • Headache
    • Nausea or vomiting
    • Fainting

If heat exhaustion is untreated, it may progress to heat stroke. Seek medical attention if symptoms worsen or last longer than one hour.


What is heat stroke?

Heat stroke, opposed to heat exhaustion, can be fatal. The key sign of heat stroke is the loss of the ability to sweat, which happens when body temperature reaches 105 degrees. At this point, the body’s brain and organ tissues begin to die. The primary cause of heat stroke is ignoring heat exhaustion.


What are the symptoms of heat stroke

Symptoms in addition to those for heat exhaustion include:

  • Loss of ability to sweat
  • Red, hot and dry skin
  • Fast or slow heart rate
  • Confusion or loss of concentration
  • Seizures
  • Unconsciousness

This is a medical emergency and you should call 911.



If you have questions, please call our Environmental Health Division at (513) 946-7800.


Download a printable version of this fact sheet here.


250 William Howard Taft Road
2nd Floor, Cincinnati, OH 45219
Phone 513.946.7800 Fax 513.946.7890