Remember how our first entry in this series mentioned hikers struggling to handle the Grand Canyon? Today, we’re delving more into the various types of heat illnesses, their symptoms, and their treatment.

Minor heat illnesses

There are several common, minor heat-related illnesses. These include:

  • Heat edema (swelling)–very common, especially in feet and ankles. Treatment for heat-related swelling is as simple as elevating someone’s legs.
  • Heat cramps–usually exercise-related cramping. Per an article published in American Family Physician (Gauer and Meyers), treatment involves fluid replacement, stretching, and massage. We’ll be referring to this article frequently throughout this blog, so keep it in mind!
  • Heat rash–caused when obstructed pores trap sweat; this irritates the skin and creates raised bumps. “Skin covered by clothing is most often affected. The rash typically resolves after moving to a colder environment, removing excess clothing…, and drying the skin” (Gauer and Meyers).

For all of these conditions, once symptoms resolve, people can return to what they were doing without requiring medical intervention.

Moderate heat illnesses – collapse and heat exhaustion

There are two types of moderate heat-related illnesses. The first is exercise-associated collapse; you may have heard or seen this called “heat syncope” before. In simplified terms, exercise-associated collapse is fainting after blood pressure lowers dramatically due to blood flow restrictions (for example, similar to the lightheadedness you can feel after standing up too quickly). Collapse usually happens immediately after strenuous exercise, and during our research we found no indication that people have to be exercising in a warm environment for this to happen. Sometimes, physical exertion is enough to trigger heat-related symptoms–although overly-warm environments certainly don’t help. Per Gauer and Meyers, “affected individuals should be placed in a supine position with legs elevated, encouraged to drink fluids, and cooled if there is concern for heat exhaustion or heat stroke.” With treatment, symptoms should end after 15-20 minutes.

One thing to remember with exercise-associated collapse is the importance of double-checking for other risk factors. People can collapse from heart problems, too; if someone collapses near you, you should look for any hints of cardiovascular trouble. Perhaps the collapsed person is in an at-risk group, or complained of heart-related symptoms before collapsing, such as chest pain. If any of these are true, and/or the collapsed patient hasn’t improved after 20 minutes, they should get medical attention before returning to exercise.

The second form of moderate illness, heat exhaustion, is “the most common heat-related illness and is the precursor to heat stroke if not recognized and treated” (Gauer and Meyers). As the most common illness, and a warning sign for something more serious, it makes sense to become familiar with heat exhaustion. Basically, during strenuous activity in a hot environment gradually raises your internal temperature until your body struggles to cool itself off (generally between 101F-104F). Symptoms include dizziness, fatigue, irritability, gut problems, and cold/clammy skin. Interestingly, Gauer and Meyers state that “mental status remains intact. Any decline in mentation, regardless of core temperatue, must be considered heat stroke.” This contradicts some other articles we found which included confusion as a symptom of heat exhaustion, but we can see why the authors made this statement. Heat stroke is a fatal medical emergency without intervention, and, as with all medical issues, it’s smart to do everything possible to prevent the worst-case scenario. If you, or someone you’re with, starts acting delirious or confused, assume that they need immediate help.

The recommended treatment for heat exhaustion involves cooling the person to at least a core temperature of 101F. This can be done by moving the suffering person to a cooler location, removing extra clothing, placing wet cloths on them (or soaking the remaining clothing with cool water), and using fans. People suffering from heat exhaustion also need rehydration. Sometimes patients won’t be able to drink by themselves, or water and electrolyte drinks may not be enough to hydrate them. If that happens, medical personnel can use an IV for intravaneous hydration. If you’re ever in doubt that a heat exhaustion victim is recovering, get help from medical professionals.

Severe illnesses – heat stroke

What is heat stroke?

Heat stroke (also known as hyperthermia) happens when internal body temperature severely overheats, typically to 105F or higher. Interestingly, an article from Frontiers in Neurology points out that the Japanese Association for Acute Medicine does not include body temperature in their heat stroke criteria, because “elderly people often do not present with high temperature even when they are already suffering from heat stroke.” The fact remains, though, that these people internally overheated.

By itself, overheating doesn’t sound so bad, but remember that such high temperatures cause massive damage. Without swift intervention, organs start shutting down.

heat stroke is complex and includes protein denaturation, endotoxin release, and thermoregulatory failure, which contribute to systemic inflammatory response syndrome [SIRS] (similar to septic shock) leading to multiorgan failure and death.

Gauyer and Meyers

In other words, your body’s response to this overheating results in it basically attacking itself. A book excerpt by Rebanta K. Chakraborty and Braken Burns from the National Library of Medicine explains this further: the body of someone suffering from SIRS releases a swarm of chemicals designed to change different systems. The SIRS response hopes to use these chemicals to drive off whatever is causing the body trauma, but it doesn’t always work. Per this excerpt, “even though the purpose is defensive, the dysregulated cytokine storm can cause a massive inflammatory cascade leading to…end-organ dysfunction and even death.”

In case, like us, you aren’t familiar with cytokines, we found a definition from the American Cancer Society: “Cytokines are small proteins that are crucial in controlling the growth and activity of other immune system cells and blood cells. When released, they signal the immune system to do its job. Cytokines affect the growth of all…cells that help the body’s immune and inflammation responses.”

Heat stroke symptoms and treatment

Hopefully this paints a clearer picture of what happens inside the body during heat stroke. On the outside, symptoms of heatstroke “include loss of consciousness, delirium, confusion, agitation, seizures, and coma” (Gauer and Meyers). Other symptoms include hot skin (with or without sweating), low blood pressure, rapid heartbeat, and rapid breathing. Per Gauer and Meyers, the organs most in danger from overheating are the brain and liver, and the longer someone spends in heat stroke without help, the worse their prognosis is.

Treatment for heat stroke looks similar to the treatment for heat exhaustion; the victim must be rapidly cooled down and rehydrated. However, people treating heat stroke victims must also pay attention to the patient’s breathing and circulation since these functions can shut down–ensuring that the patient has air takes priority even over cooling. With that said, cooling remains extremely important. If “cooling is completed within 30 minutes from collapse, the mortality rate approaches zero” (Gauer and Meyers). For people who have prolonged hyperthermia, death rates are much higher. An article by Lisa Leon and Bryan G Helwig explains that there are two kinds of heat stroke: classic heat stroke, usually affecting very elderly or very young sedentary people, and exertional heat stroke, which is the kind of heat stroke you might get while hiking the Grand Canyon in June. Per Leon and Helwig, “the hospital mortality rate in classic heat stroke ranges from 10% to 65%, whereas that of exertional heat stroke is 3% to 5%.”

People are much more likely to encounter exertional heat stroke while enjoying the summer sun, so these percentages are encouraging. With swift recognition and treatment, it’s very possible to survive heat stroke. Watch your companions this summer, and if anything seems off, don’t be afraid to ask for help! Park rangers and lifeguards all have training for heat emergencies. A pair of park rangers saved our friend’s life when he collapsed in the Canyon, and we are very grateful to them, but an ounce of prevention is worth a pound of cure. It’s much better to avoid these problems than to treat them, so take care. Stay hydrated, protected from sunlight, and vigilant, and you can have a safe, fun summer.