A nurse caring for a patient with a heat-related illness.

I've experienced heat-related illnesses with patients on opposite ends of the spectrum. I worked as a critical care nurse in an intensive care unit (ICU) for 14 years. During the summer, we often admitted one or more heat stroke victims. Usually, these were young military men doing intensive training exercises during the heat of the day.

I've also worked in a long-term care facility with seniors who don't recognize the need to consume extra liquids during the hot summer months and are vulnerable to heat-related illnesses. A summer outing can quickly become a medical emergency if the transporting bus breaks down en route between locations.

As nurses, we need to recognize the symptoms of heat-related illnesses in patients who arrive in the emergency room (ER), so we can provide prompt and expert treatment. We're also responsible for recognizing and preventing heat-related illness in patients already under our care.

An illustrated graphic explains that 3 pm is typically the hottest time of day.

5 Different Types of Heat-Related Illness

It's easy to diagnose a heat-related illness if you know the unconscious child was found in a hot car or that the adult had been working in the hot sun. However, could you identify heat exhaustion if the patient was a computer programmer? Learning what symptoms to look for will help you accurately triage the patient who has just walked into the ER.

  1. A heat rash, or prickly heat, develops when sweat gets trapped underneath the skin. It begins as a red pimple-like rash but can progress to blisters. They're sometimes filled with pus or can become hard itchy lumps. Children and seniors are at high risk for heat rash. The goal is to keep the area dry. You can put a strip of gauze beneath their breasts and armpits or use a physician-approved powder to keep the area dry.

  2. Sunburn. The symptoms of a first-degree sunburn are pink skin that is warm, sore to the touch, and may be blistered. The skin of a second-degree sunburn is red, blistered, painful, and appears wet and shiny. A person with a second-degree burn should be assessed for heat exhaustion and heat stroke. Second-degree burns are serious, and the patient may need to be admitted to the hospital for pain control if the area affected is extensive.

  3. Heat Cramps. Excessive sweating and muscle cramping may indicate heat cramps. Usually, these symptoms resolve once the patient has cooled down and drank liquid with electrolytes. If a patient presents to the ER with heat cramps, offer them fluids and assess if they need an IV.

  4. Heat exhaustion presents with tachycardia, diaphoresis or sweating, muscle cramps, nausea and vomiting, headache, clammy skin, lightheadedness, a fast, weak pulse, and fainting. Patients should be cooled with wet facecloths, given sips of water, and an intravenous (IV) started.

  5. Heat stroke is a medical emergency. Notably, the patient won’t be sweating, can have a core body temperature greater than 104 degrees Fahrenheit (F), a fast, strong pulse, hot and dry skin, confusion, seizures, and may fall into a coma. The patient needs rapid cooling, an IV started, given medication to control seizures, monitored for airway, cardiac instability, rhabdomyolysis, and transferred to an ICU.

A graphic that explains the hottest temperature on record belongs to California's Death Valley, which in 1913, reached 134 degrees Fahrenheit

What Causes Heat-Related Illness?

Have you ever wondered why just one person develops heat stroke when 50 others are performing the same military exercises or running the same race? Or how does someone develop a heat-related illness when it's not that hot outside—only 80 degrees F? There are two main contributing factors:

1. Environmental Causes

Everyone knows that high temperatures and humidity make us feel hot, but does it truly make a difference? Our bodies sweat when we're hot, and the surrounding air removes the moisture and cools us down. However, hot, muggy weather keeps the sweat from evaporating, and we begin to overheat.

Other environmental factors are wind speed, working in direct sunlight, how much heat we absorb from the objects around us, how long and hard we work, and our clothing. Many jobs require personal protective equipment (PPE), including dust or full-face masks.

2. Personal Causes

The hotter it is, the more important it is to stay hydrated by drinking adequate water or approved sports drinks. Alcohol and caffeine both have a diuretic effect and should be avoided. Having a few cold beers on a hot day can put a person into dehydration. Other factors are age, health, acclimatization to the heat, and some prescription drugs.

The Low-Down on Prescription Drugs

Many physicians, pharmacists, and patients don't know which prescription drugs increase the risk of heat-related illnesses. Some affect the hypothalamus, which regulates body temperature, while others affect renal function, cardiac output, peripheral vasodilation, and heat perception.

However, the most significant issue is that many medications reduce the ability of the body to sweat. These drugs include antidepressants, diuretics, antihistamines, and antipsychotics.

Heat-related illnesses do not have to happen, and nurses are in the position to stand in the gap and offer education to patients, families, and other healthcare providers.

Education and Prevention

We've discussed recognizing heat-related illnesses that present in the ER. However, many nurses work in pediatrics, on medical units, and in long-term care. Your patients walk outside with their parents, go out for a smoke, or leave the premises on day/weekend passes. In addition, air-conditioners in older buildings may not work well. Here are some education and prevention tips for your patients:

1. If parents take a pediatric patient outside the hospital, remind them to use sunscreen, bring a hat, and have adequate liquids in a bottle/sippy cup. Assess the child when they return for heat-related symptoms, such as a flushed face and sweat in skin folds.

2. For patients who go out for walks or to smoke on a hot day, check their prescribed medications that may affect their thermoregulatory function and advise accordingly. Remind them to wear a hat and to stand in the shade if possible.

3. Seniors living in hospitals and long-term care homes are at high risk for dehydration. They often don't know they're thirsty, and many can't get a drink for themselves. Make sure you offer fluids frequently throughout the day, and consider keeping a fluid-count sheet at their bedside.

4. If seniors go out with their families or on an outing, ensure they dress in loose, light clothing, and have a hat, sunscreen, and adequate hydration. Assess them on their return for any symptoms of heat-related illnesses.

5. When patients present to the ER with heat cramps or heat exhaustion, remind them that modifying their environment and making different personal choices can prevent further heat-related illnesses upon discharge. Advise them to watch their urine color for signs of dehydration, how to stay cool, and drink adequate amounts of water.


Heat-related illnesses can have tragic endings. Recognizing the signs of heat cramps, heat exhaustion, and heat stroke and knowing how to manage them may prevent worsening sickness and death.

Alice Blackmore, MN, RN, Content Writer

Alice is a registered nurse and healthcare writer. She has more than 20 years of nursing experience, which ranges from labor and delivery to long-term care, with pediatrics, community nursing, and critical care sandwiched in the middle.

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