Effects of extreme heat temperatures on the human body. Doctors assess the dangers.


PHOENIX — The human body is not designed to function at 118 degrees Fahrenheit. Yet that’s the life-threatening temperature expected in Arizona this weekend, on top of weeks of brutal heat.

Patients have already been arriving at Phoenix emergency rooms with sunburns, organ failure or in a coma from the extreme heat, doctors in the area told NBC News. Some people arrive with dangerously high body temperatures.

Dr. Aneesh Narang, an emergency medicine physician at Banner University Medical Center in Phoenix, has had numerous patients come in with body temperatures as high as 109 F.

“They are walking in essentially without responding and they are cooked,” he said in an interview.

What makes intense heat so deadly is that a sufferer often has disturbances in the body’s cooling mechanisms, such as the brain’s hypothalamus, which regulates temperature, that prevent a person from sweating to cool down.

“Unfortunately, you are cooking from the inside,” Narang said.

A normal body temperature typically ranges from 97 to 99 F. By comparison, a fever from an infection is typically above 100.4 F. Heat stroke occurs when body temperature is 104 F or higher.

“We’re seeing quite a lot of heat-related illness,” said Dr. Amy Axberg, an emergency medicine physician at John C. Lincoln Medical Center in Phoenix. «My patient yesterday had a temperature of 107 Fahrenheit, that’s heat stroke and that’s an emergency.»

Heat stroke can cause severe symptoms, including mental status changes, coma, and seizures. A milder form of heat-related illness, known as heat exhaustion, can cause headache, nausea, or dizziness.

At such high internal temperatures, the body’s vital organs can begin to fail, not only from the direct effect of the heat, but also from the inflammation the body produces in response.

Rapid cooling saves lives. When someone calls 911 with a heat illness, emergency medical services can put the patient in an ice bath in the field, with a special thermometer used to monitor body temperature in real time.

“We keep cooling them in that ice bath until they get to a temperature of around 100 degrees and then we quickly get them out of that ice bath,” Axberg said of the ER patient he treated.

Doctors immediately try to bring the patient’s temperature down because if not done quickly, the effects can be catastrophic.

“If they are in that state for a long time, their organs fail and there is no chance of recovery,” Narang said.

He worries that the heat hasn’t peaked yet.

“We are still in early to mid-July, and July and August are probably our two most difficult months in this area,” Narang said. «I anticipate things will get worse, unfortunately.»

More coverage on heat illness

People of all ages, not just the elderly or people with pre-existing conditions, come into the ER sick from the heat, he said. Young and active people are more prone to heat exhaustion, while both the very young and the elderly are seen to experience heat stroke.

He often sees young, healthy patients, particularly those living outside the area who may underestimate the dry heat, ending up in the ER with headaches, nausea, or a fast heartbeat from outdoor activities.

Often, they find it hard to believe that it’s really the heat that caused their symptoms, he said.

«Regardless of how healthy you are when you’re out in the heat, if you’re not hydrating well, you can quickly get into trouble.»

Medications Can Block Warning Signs

Certain prescription medications, such as psychiatric medications or diuretics for high blood pressure and beta-blockers that slow the heart rate, can mask warning signs that your body is in trouble from heat.

“Psychiatric drugs can work on the hypothalamus, which regulates temperature, so some of those drugs can prevent you from sweating,” he said, referring to drugs like antidepressants. «It can affect the ability to thermoregulate, and therefore patients can have problems that way.»

However, the doctors urged the patients not to stop taking their prescription medications because of the heat.

Right now, ER doctors say, their ERs aren’t overwhelmed like they were during Covid, though they’re concerned about 110-F temperatures projected across the region on Saturday and Sunday.

«Overall, we’re doing well, but during the heat of the day, it can often become overwhelming with the number of patients coming in,» said Dr. Brian Hess, emergency medical director at several Abrazo Health emergency departments. in arizona “We have to accommodate higher volumes of EMS traffic during those very hot periods.”

He is particularly concerned about people with substance use disorders or who have housing problems.

«If you have a substance use disorder and you’re intoxicated, you don’t have the cues to recognize that you’re experiencing a physiological condition that can be very dangerous,» Hess said.

People with dementia may not be able to recognize the warning signs of heat exhaustion. Heart failure patients who are advised not to drink a lot of fluids should also be more cautious, she said.

Stages of heat exhaustion, heat stroke

At triple-digit temperatures, the first symptoms of heat exposure can occur in as little as 15 minutes, Hess said. For more severe heat stroke, symptoms usually take a couple of hours of exposure, depending on risk factors. However, once heat stroke begins, body temperature can rise to 106 F in as little as 10 minutes. according to the Centers for Disease Control and Prevention.

Early symptoms may include:

  • Heat cramps or severe muscle spasms as a result of salt and water loss after exertion, most often in the hands, calves, and feet.
  • Dizziness.
  • Nausea.
  • Heart palpitations.
  • Difficulty breathing.

“The most serious signs are changes in your mental state,” Axberg said. «You could be confused, slurred, or just don’t feel like yourself.»

While it’s best to stay indoors as much as possible, if people are getting outdoors, taking a walk, or playing a round of golf, hydrating is a great way to avoid potential problems.

“I always recommend a glass of water before you have your cup of coffee in the morning to prevent dehydration from catching you off guard,” Hess said.

One of the misconceptions people have is that if they’re not thirsty, they probably aren’t dehydrated.

«That’s not true,» Narang said. «By the time you’re thirsty, you’re way behind the eight ball.»

Fortunately, if heat stroke is treated early, you will likely recover.

After being found unconscious on the street, the Axberg patient with a body temperature of 107 F is now eating and drinking.

“Yesterday they weren’t even breathing,” Axberg said. «The treatment for heat stroke is rapid cooling, and if we can do that effectively and efficiently, then patients will be fine.»

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