More than 91 million Americans in the South and Southwest were under heat warnings from the National Weather Service on Tuesday, and 79 million of them were expected to experience dangerous heat — defined by the agency as a heat index of over 103 degrees Fahrenheit.
(The heat index combines heat and humidity. For example, if the temperature is 98°F, the heat index will still be dangerous if the relative humidity is greater than 40%.)
Cities with dangerous heat indexes include Phoenix and Tucson, Arizona, and Houston and Austin, Texas, all of which have been brooding under a persistent heat dome for weeks.
On Tuesday, Phoenix recorded 19 consecutive days of temperatures above 110°F, breaking his previous record of 18 days, set in 1974. Due to climate change and El Niño, several days this month have been the warmest on record in the world.
These are the dangers of extreme heat and how to minimize them.
The threat to health
Such high temperatures, especially when combined with high humidity – which hinders the evaporation of sweat, the body’s cooling mechanism – can cause heat-related illnesses such as heat exhaustion and heatstroke, and increase the risk of conditions such as heart failure.
According to the Centers for Disease Control and Prevention, extreme heat is the deadliest weather hazard in the United States, killing an average of 700 people per year and causing more than 67,000 emergency room visits.
“This is the worst summer in recent memory,” Frank LoVecchio, an emergency room doctor at a Phoenix hospital, told NBC News, adding that his hospital is overcrowded because 20% of current patients are there because of heat-related illnesses .
Such figures are likely an undercount, the CDC says, because heat-related deaths are often misclassified.
Who is the most vulnerable
Because heat taxes the heart and respiratory system, people with respiratory or cardiovascular conditions are at increased risk from heat, as are people whose bodies are less adept at regulating their temperature, such as infants, pregnant women and the elderly.
According to the National Oceanic and Atmospheric Administration, lower-income urban areas, which have more pavement, fewer trees and less grass, can be up to 20 degrees warmer than nearby suburbs. People with lower incomes, who are more likely to have no air conditioning in their homes, are at greater risk of heat-related illness.
People who work outdoors are more exposed to the heat, and the Occupational Safety and Health Administration says workers in extreme heat are more likely to have dangerous accidents, such as falling from a roof or mishandling machinery. The Republican-led Texas Legislature recently overturned workplace heat safety requirements in Dallas and Austin, leaving workers without legal guarantees of water breaks.
How to prevent health problems
The NWS and other weather and public health authorities recommend the following key strategies to beat the heat:
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Drink plenty of water, whether you are thirsty or not. Avoid alcohol as it increases dehydration.
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Avoid strenuous activities. If you have to exercise or work outside, try to do this very early or late, when the temperature is lower.
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Wear sunscreen to prevent sunburn, which contributes to dehydration and makes it harder for your body to cool down.
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Stay in air-conditioned places. “If your home does not have air conditioning, go to the mall or public library,” the CDC advises. If you don’t have access to air conditioning, a cool shower or bath can help.
Know your risk
You can view the heat index at Heat.gov, a website launched last year by the Biden administration as part of its efforts to combat the growing threat of extreme heat.
Dehydration is one of the biggest risks of extreme heat. If you don’t drink enough fluid to cool your body through sweat, your body temperature can rise and cause heatstroke, a potentially fatal condition in which your body becomes so hot that it can damage your brain, heart and kidneys.
Pay attention to the symptoms of heat exhaustion, which occur sooner and can progress to heat stroke if left untreated. Symptoms include headache, nausea, dizziness and weakness.
If you sweat profusely and your body temperature feels warm, or if you develop symptoms of heatstroke such as vomiting, flushed skin, rapid breathing, or palpitations, treat it immediately.
What to do if you have symptoms
For heat exhaustion, the Mayo Clinic recommends lying with your legs above your heart and drinking water or sports drinks. If possible, take a cool shower, lie in a body of water, or place towels soaked in cool water on your body.
If symptoms do not improve within an hour, or if you have heat stroke, take a cold bath or apply ice packs to quickly lower your body temperature and seek emergency medical attention.
