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.

Confirmed Cases: 57162

Reported Deaths: 1660
CountyConfirmedDeaths
Hennepin18197820
Ramsey7047261
Dakota4049103
Anoka3410113
Stearns284220
Washington193843
Nobles17496
Olmsted163523
Scott141017
Mower10842
Rice10028
Blue Earth8595
Wright8205
Carver7922
Clay75240
Kandiyohi6771
Sherburne6577
St. Louis45319
Todd4202
Lyon4163
Freeborn3551
Steele3331
Nicollet32013
Benton3103
Watonwan2990
Winona24916
Crow Wing21313
Martin2045
Le Sueur2021
Beltrami2000
Chisago1821
Otter Tail1793
Goodhue1778
Cottonwood1730
Becker1471
Pipestone1439
McLeod1400
Unassigned14040
Polk1353
Itasca13412
Douglas1320
Waseca1300
Pine1280
Carlton1260
Dodge1230
Murray1221
Isanti1100
Chippewa991
Brown852
Faribault840
Meeker832
Morrison821
Wabasha820
Sibley802
Rock750
Koochiching743
Pennington731
Jackson700
Mille Lacs683
Cass622
Fillmore610
Renville605
Lincoln540
Swift521
Grant511
Yellow Medicine490
Roseau460
Pope450
Houston390
Norman370
Hubbard320
Redwood320
Marshall290
Kanabec281
Wilkin283
Aitkin270
Mahnomen241
Wadena230
Big Stone220
Red Lake200
Lake180
Stevens160
Clearwater150
Traverse100
Lac qui Parle60
Kittson30
Cook20
Lake of the Woods10

Iowa Coronavirus Cases

Data is updated nightly.

Confirmed Cases: 46100

Reported Deaths: 887
CountyConfirmedDeaths
Polk9781203
Woodbury365651
Black Hawk302262
Linn214587
Johnson195915
Dallas179635
Buena Vista178612
Scott161512
Dubuque154929
Marshall139424
Pottawattamie122723
Story111714
Wapello85032
Muscatine83048
Webster7366
Crawford7213
Sioux6022
Cerro Gordo57917
Tama53929
Warren5341
Jasper45825
Wright4441
Plymouth4438
Louisa37814
Dickinson3754
Clinton3213
Washington28810
Hamilton2411
Boone2312
Franklin2256
Bremer1927
Clarke1883
Carroll1821
Emmet1812
Clay1711
Shelby1691
Hardin1660
Marion1550
Allamakee1504
Poweshiek1508
Benton1451
Jackson1411
Des Moines1392
Mahaska13617
Floyd1312
Guthrie1285
Jones1242
Cedar1201
Hancock1172
Butler1152
Buchanan1141
Henry1143
Pocahontas1141
Lyon1060
Madison1052
Clayton993
Cherokee981
Harrison980
Lee973
Taylor930
Humboldt921
Delaware911
Iowa901
Monona900
Winneshiek861
Mills830
Calhoun822
Fayette810
Sac810
Palo Alto800
Kossuth780
Osceola780
Jefferson770
Winnebago770
Mitchell760
Page760
Grundy741
Union721
Monroe677
Worth610
Chickasaw510
Davis501
Lucas504
Howard490
Cass481
Montgomery453
Appanoose433
Greene380
Fremont350
Van Buren331
Keokuk311
Ida290
Audubon281
Decatur220
Adair210
Ringgold211
Wayne181
Adams160
Unassigned00
Rochester
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