More than 91 million Americans in the South and Southwest were subject to National Weather Service heat alerts on Tuesday, and 79 million of them are expected to experience dangerous heat – defined by the agency as a heat index above 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 above 40%).
Cities with dangerous heat indexes include Phoenix; Tucson, Ariz.; Houston and Austin, Texas, all of which have been sweltering under a dome of lingering heat for weeks. Phoenix has had 18 consecutive days above 110°F – a tie with its all-time high, which it is expected to break on Tuesday.
Due to climate change and El Niño, several days this month were the hottest in the world on record.
These are the dangers of extreme heat and how to minimize them.
The health threat
Such high temperatures, especially when combined with high humidity – which inhibits 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 diseases such as heart failure.
Extreme heat is the deadliest climate hazard in the United States, killing an average of 700 people a year and causing more than 67,000 annual emergency room visits, according to the Centers for Disease Control and Prevention.
“This is the worst summer in recent memory,” Frank LoVecchio, an emergency physician at a Phoenix hospital, told NBC News, adding that his hospital is overcrowded because 20% of his current patients are there for heat-related illnesses. .
Those numbers are likely an undercount, according to the CDC, because heat-related deaths are often misclassified.
Who is most vulnerable
Because heat stresses the heart and respiratory system, people with respiratory or cardiovascular conditions are at high risk for heat, as are people whose bodies are less able to regulate their temperature, such as babies, pregnant women and old people.
According to the National Oceanic and Atmospheric Administration, low-income urban areas, which have more sidewalks, fewer trees and less grass, can be up to 20 degrees warmer than nearby suburbs. Low-income people, who are more likely to have no air conditioning at home, are more likely to suffer from heat-related illnesses.
People who work outdoors are more exposed to heat, and the Occupational Safety and Health Administration says workers in extreme heat are more likely to have dangerous accidents, such as falling off a roof or mishandling machinery. The Republican-led legislature in Texas recently rolled back workplace heat safety requirements in Dallas and Austin, leaving workers without legal water shut-off guarantees.
How to prevent health problems
The NWS and other meteorological and public health authorities recommend the following key strategies for beating the heat:
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Drink plenty of water whether you are thirsty or not. Avoid alcohol, which increases dehydration.
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Avoid strenuous activities. If you must exercise or work outside, try to do it very early or late when the temperatures are lower.
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Wear sunscreen to prevent sunburn, which contributes to dehydration and prevents your body from cooling down.
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Stay in air-conditioned places. “If your home doesn’t have air conditioning, go to the mall or the public library,” advises the CDC. If you don’t have access to air conditioning, a cool shower or bath can help.
Know your risk
You can check out the Heat Index on Heat.gov, a website launched by the Biden administration last year as part of its effort to combat the growing threat of extreme heat.
Dehydration is one of the major risks of oppressive heat. If you don’t drink enough fluid to cool your body through sweating, your body temperature can rise and cause heatstroke, a life-threatening condition in which your body becomes so hot that it can damage your brain, heart, and your kidneys.
Keep an eye out for symptoms of heat exhaustion, which occurs before and can turn into heatstroke if left untreated. Symptoms include headache, nausea, dizziness and weakness.
If you are sweating profusely and your body temperature is high, or if you develop symptoms of heat stroke such as vomiting, flushing of the skin, rapid breathing, or rapid heartbeat, treat it immediately.
What to do if you have symptoms
In case of heat exhaustion, the Mayo Clinic advises that you lie with your legs above your heart and drink water or sports drinks. If possible, take a cool shower, dip in a body of water, or apply towels soaked in cold water to your body.
If symptoms do not improve within an hour or if you have heatstroke, take a cold bath or apply ice packs to quickly lower your body temperature and seek emergency medical attention.