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How heat waves can kill -- and how to stay safe

As a potentially record-breaking heat wave grips the nation thi...

Posted: Jul 19, 2019 5:55 AM

As a potentially record-breaking heat wave grips the nation this weekend, doctors are warning people to find air conditioning and stay cool -- or risk a trip to the emergency room and a hospital ice bath.

Extreme temperatures are the most deadly weather events in the United States, consistently killing more people than hurricanes and tornadoes combined. Over the next few days, more than 85% of the lower 48's population will see temperatures above 90°F (32.2°C), according to CNN meteorologist Dave Hennen, and more than half will see temperatures in excess of 95°F (35°C).

While dehydration is a common concern as it gets warmer, "the most worrisome consequence" of high heat is heat stroke, said Dr. Scott Dresden, an assistant professor of emergency medicine at Northwestern University. Heat stroke can cause confusion, seizures and even death, he said.

The condition, also known as hyperthermia or heat illness, occurs when someone's body temperature rises above 104°F (40°C). Usually, we cool ourselves off by sweating and widening our blood vessels, bringing heat to the surface of our skin and letting it dissipate.

But sweating becomes ineffective as humidity rises above 75%. Our bodies can only let off heat when the outside environment is cooler than our internal body temperature of 98.6°F.

In older adults, medications can also impair heat regulation, Dresden said, and children face additional challenges controlling their body temperature as it gets hotter. That can lead to dangerous, sometimes deadly, consequences.

"The first symptoms that people will start to feel can often be cramping and dizziness," Dresden said. Those could be managed at home by getting out of the heat and drinking lots of fluids, he added.

"Other, more serious symptoms are if somebody actually passes out or collapses from the heat," he said. That requires medical attention, and "if friends or family or co-workers are noticing that somebody's confused, that is also a severe sign of possible heat stroke" that would warrant a trip to the hospital.

Left untreated, extreme heat stroke can trigger a dangerously fast heart rate and cause bodily enzymes to stop functioning. Ultimately, multi-organ system failure and death can occur.

Ice baths and wet sheets

Medical interventions for heat-related injuries aren't always the most pleasant. "We typically use ice baths in our emergency department," Dresden said. "We'll do cold water immersion."

That can rapidly cool someone's body temperature, but patients are sometimes treated before they even arrive at the hospital. "Our Chicago fire department will often pack a patient's neck, armpits and groin in ice packs" to target major blood vessels, Dresden said.

Wet sheets and large fans are also used in the hospital to cool patients, especially if ice baths aren't available. But as an emergency room doctor, Dresden emphasized that preventing heat stroke is almost always easier than treating it.

"Especially for young and healthy people, if you're going to be exercising, do it when it's cooler or do it in an air-conditioned gym when it's really hot outside," he said. "For everyone else -- for everyone really -- wear lighter clothing and make sure that you're drinking lots of fluids."

People can gauge how well they're hydrated by looking at their urine. Too dark, Dresden said, and you probably need more water. That can prevent dehydration, which can lead to muscle cramps, dizziness and severe electrolyte abnormalities, he added.

But above all, "try to get out of the heat whenever you can," Dresden said. Many cities, including Chicago and New York, have opened cooling centers that are free to access.

Lives at risk as the climate warms

Experts say that heat waves like this one are only made worse by the ongoing impact of climate crisis. According to last year's National Climate Assessment, the number of hot days in the US is increasing and we can expect to see many more extreme heat days in the future.

Heat waves have also increased in frequency, rising from an average of two per year to six per year in the last five decades. The threat is especially pronounced in the Northeast, where "the frequency, intensity, and duration of heat waves is expected to increase" due to climate change.

By 2050, the assessment found, the Northeast can expect at least 650 more deaths each year because of extreme heat.

California Coronavirus Cases

Data is updated nightly.

Confirmed Cases: 574231

Reported Deaths: 10476
CountyConfirmedDeaths
Los Angeles2105434998
Riverside41983820
Orange40527726
San Bernardino36072546
San Diego32975594
Kern24440171
Fresno17846171
Alameda13631209
San Joaquin12864223
Santa Clara12694205
Sacramento12040177
Tulare10862196
Stanislaus10264169
Imperial9693244
Contra Costa9404139
Ventura863492
San Francisco762367
Santa Barbara670469
San Mateo6318120
Merced573670
Monterey544635
Marin540481
Kings445356
Solano427441
Sonoma367047
Madera246339
Placer231922
San Luis Obispo225416
Yolo183444
Santa Cruz12436
Butte12388
Napa107411
Sutter9527
San Benito7654
El Dorado7552
Lassen6830
Yuba6464
Mendocino47210
Shasta45910
Colusa3914
Glenn3603
Nevada3571
Humboldt2864
Tehama2761
Lake2402
Amador1822
Mono1581
Tuolumne1553
Calaveras1471
Inyo1063
Siskiyou1020
Del Norte1000
Mariposa622
Plumas360
Modoc50
Trinity50
Sierra40
Alpine20
Unassigned00
Chico
Scattered Clouds
88° wxIcon
Hi: 93° Lo: 63°
Feels Like: 88°
Oroville
Clear
91° wxIcon
Hi: 95° Lo: 64°
Feels Like: 91°
Paradise
Scattered Clouds
88° wxIcon
Hi: 87° Lo: 66°
Feels Like: 88°
Chester
Scattered Clouds
83° wxIcon
Hi: 84° Lo: 54°
Feels Like: 83°
Red Bluff
Clear
93° wxIcon
Hi: 96° Lo: 66°
Feels Like: 93°
Willows
Scattered Clouds
88° wxIcon
Hi: 98° Lo: 59°
Feels Like: 88°
We won't be as hot today, but the threat of thunderstorms will result in elevated fire danger this afternoon and tonight. The heat ramps up through your extended forecast.
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