How does extreme heat affect the body and what can be done about it? | Health

A dangerous heat wave threatens much of the southwestern US, with millions of people under a heat alert for the second week in a row. On Tuesday, temperatures were forecast to rise to 102°F in Sacramento, California, and on Wednesday to 111°F in Phoenix, Arizona. The sweltering heat is expected to hit the East Coast on Friday.

Health experts and climate scientists described the effects of extreme heat on the human body, which populations are most at risk, and ways to mitigate it.

What is heat stress and what causes it?

It occurs when the body experiences a buildup of heat, at a level higher than it can release. “The human body has this fantastic ability to cool itself through the evaporation of sweat,” said Uwe Reischl, a professor in the school of public and population health at Boise State University. But even when the body produces sweat, evaporation can be limited due to humidity in the air.

Another factor that causes body temperature to increase is when a person wears clothing that prevents sweat from leaving the skin. And when the body does not have enough water, it becomes dehydrated to the point that it can no longer produce sweat.

How does this relate to the current heat dome phenomenon?

Hot air can hold more moisture than cold air. “So the warmer the thermal dome, the higher the humidity levels,” Reischl said. Urban environments with many buildings, paved roads, and parking lots exacerbate the likelihood of heat stress as they absorb heat from the sun (and release it) throughout the day.

What are some signs of heat stress?

“Heat stress is a spectrum,” said Kristie Ebi, a professor of environmental and occupational health at the University of Washington. Symptoms can range from small reddish blisters on the hands to fainting. In extreme cases, if the body temperature rises above 39°C (103°F), it can cause heat stroke, which can cause the brain and other internal organs to swell, and can be fatal.

who is more Affected by heat stress?

Children, the elderly and pregnant women are among the most vulnerable to heat stress. “Athletes and outdoor workers may be at much higher risk for heat stress,” Ebi said, since the more people move or work, the more heat their bodies have to eliminate. These circumstances are more complicated for people like farmworkers, who need protection from physical or chemical hazards, such as pesticides. They should wear protective clothing, which can interfere with their body’s ability to evaporate sweat.

How does the human body recover from heat stress?

“When we are exposed to high temperatures, we need time for our bodies to cool down, and that usually happens at night,” Ebi said. (But since 1970, summer nighttime temperatures have risen 3°F on average, meaning people have less respite at night.)

“In addition to resting, the body needs to rehydrate,” Reischl said, adding that people should drink more water than they normally would.

What can people do to mitigate heat stress?

Avoid strenuous outdoor activities, drink fluids, stay out of the sun, and spend more time in air-conditioned places, such as cooling centers.

What are some ways to stay cool without air conditioning?

Putting your feet in cold water, placing cold towels around your neck, sitting in front of an electric fan, and spraying yourself with water are effective ways to cool down. Just like lowering the blinds in the house during the day and opening the windows at night.

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