Heat Related Illness: Risk Factors, Prevention, Symptoms, and Treatment

Whether you are working outside, working out outside, or enjoying some fun in the sun, high temperatures, especially when coupled with high humidity and direct sunlight, can be extremely dangerous, potentially leading to illness, organ damage and even death. According to the CDC, “more than 600 people die from extreme heat every year.” Heat related illness affects people differently but keeping an eye out for symptoms and actively working to prevent overheating can help.

Risk Factors

Heat illness can strike anyone, but people 65 and older, children under two years of age and those dependent on others due to disability, chronic disease, or mental illness, along with workers who must perform strenuous labor while exposed to high heat, are at the highest risk for heat related illness.

Additional personal factors, such as obesity, fever, dehydration, heart disease, poor circulation, sunburn, and prescription drug and alcohol use all can play a role in whether a person can cool off properly. 

Another factor to keep in mind, is high humidity levels. According to the CDC, when extreme heat is coupled with high humidity, our body struggles at an extreme level to regulate itself at the speed necessary: our body cannot release heat as fast as it needs to in high humidity because sweat doesn’t evaporate as quickly.


Despite higher risk for some groups of people, anyone can suffer from heat related illness. Below are some prevention methods from the CDC that everyone can keep in mind to protect themselves and others around them.

  • Limit outdoor activity, especially when the sun is at its hottest
  • Stay in an air-conditioned indoor location as much as possible
  • Use air conditioning in your vehicle
  • Don’t use the stove or oven to cook
  • Drink plenty of fluids even if you don’t feel thirsty
  • Take cool showers or baths to cool down
  • Wear and reapply sunscreen as indicated on the package
  • Pace your activity
  • Wear loose, lightweight, light-colored clothing
  • Seek medical care right away if you or someone around you has symptoms of heat-related illness
  • Never leave children or pets in cars
  • Check the local news for health and safety updates
  • If someone is dependent on you, ensure they are drinking enough water and pay attention to their need for air conditioning or other assistance to cool down

According to OSHA, some additional tips for employers to keep in mind to ensure workers are safe in the heat:

  • Provide water, frequent rest breaks, and shade
  • Allow time to build a tolerance for working in the heat
  • Offer training on the hazards of heat exposure and how to prevent illness
  • Develop an emergency action plan on what to do if a worker shows signs of heat-related illness

Symptoms & Treatment

According to the National Safety Council, there are two different types of heat related illness to watch for: heat exhaustion and heat stroke.

Heat exhaustion happens when the body loses excessive water and salt, typically due to sweating. Symptoms include:

  • Sweating
  • Pale, ashen or moist skin
  • Muscle cramps (especially for those working or exercising outdoors in high temperatures)
  • Fatigue, weakness or exhaustion
  • Headache, dizziness or fainting
  • Nausea or vomiting
  • Rapid heart rate

If you or someone around you is suffering from heat exhaustion:

  • Move victims to a shaded or air-conditioned area
  • Give water or other cool, nonalcoholic beverages
  • Apply wet towels, or have victims take a cool shower

Uncontrolled heat exhaustion can evolve into heat stroke, which is the advanced stage manifestation of heat exhaustion. Symptoms include:

  • Body temperature above 103 degrees
  • Skin that is flushed, dry and hot to the touch; sweating has usually stopped
  • Rapid breathing
  • Headache, dizziness, confusion or other signs of altered mental status
  • Irrational or belligerent behavior
  • Convulsions or unresponsiveness

If someone is suffering from heat stroke, get help immediately:

  • Call 911
  • Move the victim to a cool place
  • Remove unnecessary clothing
  • Immediately cool the victim, preferably by immersing up to the neck in cold water (with the help of a second rescuer)
  • If immersion in cold water is not possible, place the victim in a cold shower or move to a cool area and cover as much of the body as possible with cold, wet towels
  • Keep cooling until body temperature drops to 101 degrees
  • Monitor the victim’s breathing and be ready to give CPR if needed


  • Force the victim to drink liquids
  • Apply rubbing alcohol to the skin
  • Allow victims to take pain relievers or salt tablets

Being outdoors in extreme heat, especially with contributing risk factors or while exerting energy through manual labor or physical activity, can lead to heat related illness, which is serious and life threatening if not handled quickly and appropriately. Make sure you are aware and prepared.


OSHA, “Working Safely in Hot Weather”

CDC, “Keep Your Cool in Hot Weather”

National Safety Council, “Learn How to Avoid Heat-related Illnesses and Death”