Heat-Related Illnesses

Ensuring that your staff recognizes the symptoms of—and knows how to treat—heat-related illness can mean the difference between life and death. This tip reviews how to recognize and treat common heat-related illnesses, as well as provides best practices for prevention. 

Know Who Is at Greatest Risk

Although anyone can suffer from a heat-related illness, some people are at greater risk. The following groups may be more susceptible to heat-related illness:

  • Infants and young children
  • Seniors (aged 65 or older)
  • The overweight or obese
  • Those with pre-existing medical conditions, particularly heart disease or high blood pressure
  • Those taking certain prescription medications, particularly for depression, insomnia, or circulatory issues

Recognizing and Treating Heat-Related Illness

Prolonged exposure to extreme heat can push the human body beyond its limits. In extreme heat and high humidity, evaporation is slowed and the body must work extra hard to maintain a normal temperature. Most heat illnesses occur because the victim was overexposed to heat or overexercised for his or her age and physical condition. The most serious heat-related illnesses are heat cramps, heat exhaustion, and heat stroke.

Heat Cramps

Heat cramps are often the first signal that the body is having trouble with the heat.


  • Muscle pains or spasms due to heavy exertion.


  • Go to a cooler place and rest in a comfortable position.
  • Lightly stretch the affected muscle and replenish fluids.
  • Drink a half glass of cool water every 15 minutes.
  • Do not drink caffeinated liquids, as they can make conditions worse.
  • Stop all activity, and sit quietly in a cool place.
  • Avoid strenuous activity for several hours after cramps subside.
  • Seek medical attention if heat cramps do not subside after one hour.

Heat Exhaustion

Heat exhaustion typically occurs when people exercise heavily or work in a hot, humid place where body fluids are lost through heavy sweating. Blood flow increases to the skin and decreases to vital organs, resulting in a form of mild shock. If not treated, the victim's condition will worsen. Body temperature will keep rising and the victim may suffer heat stroke.


  • Cool, moist, pale, or flushed skin
  • Heavy sweating
  • Muscle cramps
  • Tiredness
  • Weakness
  • Dizziness
  • Headache
  • Nausea or vomiting
  • Fainting


  • Move the person to a cooler place and have him or her rest in a comfortable position.
  • Remove or loosen tight clothing and apply cool, wet cloths, such as towels or sheets.
  • If the person is conscious, give him or her cool water to drink (four ounces every 15 minutes).
  • Do not give liquids that contain alcohol or caffeine.
  • Watch carefully for changes in the person's condition.
  • Seek medical attention immediately if:
  • Symptoms are severe.
  • The victim has heart problems or high blood pressure.
  • Symptoms worsen or last longer than one hour.

Heat Stroke

Heat stroke is a life-threatening condition in which the victim's temperature-control system stops working. During heat stroke, body temperature can rise so high that brain damage or death may result unless the victim is cooled immediately.


  • Extremely high body temperature (above 103°F)
  • Hot, red skin (Note: if the person was sweating from heavy work or exercise, skin may be wet; otherwise, it will feel dry.)
  • Rapid, weak pulse
  • Rapid, shallow breathing
  • Throbbing headache
  • Dizziness
  • Nausea
  • Confusion
  • Changes in consciousness


Heat stroke is a life-threatening situation. Help is needed fast. Call 911 and do the following:

  • Move the person to a cooler/shaded area.
  • Keep the person lying down.
  • Cool the victim rapidly using any method available, such as a cool bath or applying wet sheets around the body and fanning.
  • Monitor body temperature, and continue cooling efforts until the body temperature drops to 101- 102°F.
  • If there is vomiting, keep the airway open by turning the victim on his or her side.
  • Do NOT provide fluids if the victim:
  • Refuses water.
  • Is vomiting.
  • Is experiencing changes in consciousness.
  • Is experiencing muscle spasms.
  • If the emergency medical team is delayed, call a hospital emergency room for further instructions.

Preventing Heat-Related Illness

The following techniques will help limit the potential for heat-related illness:

  • Drink fluids regularly, regardless of your activity level. Do not wait until you are thirsty to drink.
  • Avoid liquids that contain large amounts of sugar, as these cause you to lose more body fluids.
  • Avoid very cold drinks, because they can cause stomach cramps.
  • Wear lightweight, light-colored, loose-fitting clothing.
  • Limit time outdoors. Seek shelter in an air-conditioned building. If your building does not have air conditioning, stay on the lowest floor.
  • When the temperature reaches the 90s, electric fans will NOT help prevent heat-related illness. Taking a cool shower or bath, or moving to an air-conditioned location is the best way to cool off without air conditioning.
  • NEVER leave anyone in a closed, parked vehicle.

If you must be out in the heat:

  • Limit your outdoor activity to morning and evening hours.
  • Drink two to four glasses of cool water per hour.
  • Rest frequently in shady areas.
  • Protect yourself from the sun by wearing a wide-brimmed hat and sunglasses.
  • Wear broad-spectrum (UVA/UVB protection) sunscreen of SPF 15 or higher.


For more information about extreme heat emergencies and illness, check out the following resources:

Centers for Disease Control and Prevention

City of New York

Environmental Protection Agency

  • Excessive Heat Events Guidebook , designed to help community officials, emergency managers, meteorologists, and others plan for and respond to excessive heat events.