Heat-related illnesses occur when the body is unable to cool itself by sweating, leading to a buildup of heat in the body (hyperthermia). Similar to the way extreme cold can lead to hypothermia, exposure to high temperatures over a prolonged period of time can be deadly. According to the Centers for Disease Control and Prevention (CDC), heat-related illnesses claim about 300 lives in the United States each year.

There are several types of heat illness, including heat stroke, heat exhaustion, heat cramps, heat rash and sunburn. Of these, heat stroke and heat exhaustion are the most common (with the exception of sunburn) and the most dangerous. Heat stroke can be fatal, and heat exhaustion can lead to heat stroke if it goes untreated. Signs and symptoms of these two conditions are quite different and learning to recognize them can save lives.

Factors that increase a person’s risk of developing a heat-related illness include:

• Weight (overweight and obese people are at higher risk)
  
  
• Mental illness (people who are less likely to take basic precautions or are taking medications that increase their risk)
  
  
• Medications that increase a person’s sensitivity to the sun or heat (e.g., ACE inhibitors, diuretics, psychotropics)
  
  
• Existing fever or sunburn, dehydration, or alcohol use
  
  
• Some illegal drugs (e.g., cocaine)

Tips for preventing heat-related illness include:

According to the CDC, people with heart disease and elderly people should be checked on at least twice a day during a heat wave and observed closely for signs of heat stroke or heat exhaustion. Children should be checked more frequently. People who suspect a heat-related illness in themselves or a loved one should contact a physician immediately. A quick reference chart at the end of this article can help individuals to quickly recognize the difference between heat stroke and heat exhaustion and administer first aid accordingly.