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 7:55 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.

Minnesota Coronavirus Cases

Data is updated nightly.

Cases: 485655

Reported Deaths: 6558
CountyCasesDeaths
Hennepin1007641586
Ramsey43106801
Dakota36297390
Anoka33293385
Washington22078256
Stearns18734201
St. Louis14805262
Scott13290107
Wright12526115
Olmsted1178988
Sherburne872872
Carver772640
Clay691587
Rice670491
Blue Earth594735
Kandiyohi579574
Crow Wing520681
Chisago499045
Otter Tail482170
Benton446490
Winona418349
Mower404731
Douglas392668
Nobles387047
Goodhue385768
Polk343162
McLeod339349
Beltrami337951
Morrison324547
Itasca313046
Lyon313044
Becker311342
Isanti306154
Steele300411
Carlton300149
Pine282016
Freeborn280723
Nicollet258641
Todd248030
Brown245037
Le Sueur235320
Mille Lacs227447
Cass220024
Waseca208717
Meeker207434
Martin189528
Wabasha18653
Roseau180217
Hubbard160640
Houston157314
Dodge15224
Renville149640
Redwood147027
Fillmore13728
Chippewa136335
Cottonwood134820
Pennington134416
Wadena130920
Faribault123017
Aitkin118833
Sibley117310
Watonwan11738
Rock115714
Kanabec107519
Pipestone101424
Yellow Medicine97617
Murray9448
Jackson93510
Swift87918
Pope8045
Marshall77815
Stevens7418
Lake74018
Clearwater71914
Lac qui Parle68416
Wilkin67110
Koochiching61811
Big Stone5163
Lincoln5062
Grant4918
Norman4788
Unassigned46768
Mahnomen4417
Kittson40921
Red Lake3625
Traverse3055
Lake of the Woods2191
Cook1180

Iowa Coronavirus Cases

Data is updated nightly.

Cases: 362827

Reported Deaths: 5440
CountyCasesDeaths
Polk58260551
Linn20670313
Scott18318210
Black Hawk16258292
Woodbury14979211
Johnson1384874
Dubuque13562194
Dallas1138690
Pottawattamie10791143
Story1024945
Warren556674
Clinton543784
Cerro Gordo533782
Webster519587
Marshall497272
Sioux494869
Buena Vista474537
Des Moines458861
Muscatine452291
Wapello4345108
Jasper417766
Plymouth395378
Lee375452
Marion359169
Jones294154
Henry293337
Carroll286249
Bremer280854
Crawford275135
Boone259730
Washington254347
Benton253854
Mahaska224746
Jackson221638
Dickinson217840
Tama213765
Kossuth208555
Clay193625
Hamilton192142
Delaware189140
Winneshiek189127
Buchanan185729
Fayette185235
Page183319
Hardin181439
Wright179931
Harrison179469
Cedar178523
Clayton168154
Butler167231
Mills163020
Floyd162741
Cherokee154836
Madison154718
Poweshiek154330
Hancock147130
Allamakee146747
Lyon145941
Iowa145023
Appanoose139247
Grundy139230
Jefferson138734
Winnebago138631
Cass134751
Calhoun133811
Mitchell130940
Louisa128241
Union126631
Chickasaw125215
Sac124618
Emmet121740
Shelby121733
Franklin118319
Humboldt117925
Guthrie116628
Palo Alto105221
Montgomery104136
Howard102921
Clarke100420
Unassigned9900
Keokuk98229
Monroe93328
Adair92128
Ida91432
Pocahontas85419
Davis83123
Monona81627
Greene77510
Lucas74021
Osceola70615
Worth6997
Taylor66612
Fremont5909
Decatur5829
Van Buren56118
Ringgold52320
Wayne48921
Audubon4889
Adams3274
Rochester/St. Mary'S
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Austin
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Mild conditions expected this week
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