What is 'happy hypoxia'? Why doctors are concerned by the latest COVID-19 symptom

·6 min read
BERLIN, GERMANY - APRIL 28: In this photo illustration, a young woman uses an oximeter to measure her pulse and her peripheral oxygen saturation level during the coronavirus crisis on April 28, 2020 in Berlin, Germany. The device is useful in checking for low or declining oxygen saturation, which might indicate onsetting pneumonia, a common condition among Covid-19 patients who wind up in intensive care.   (Photo by Sean Gallup/Getty Images)
A woman uses an oximeter to measure her pulse and her peripheral oxygen saturation level. The device is useful in checking for low or declining oxygen saturation, which might indicate onsetting pneumonia, a common condition among COVID-19 patients who wind up in intensive care. (Sean Gallup/Getty Images)

COVID-19 has caused some unusual symptoms, including COVID toes and a loss of taste and smell. But now there’s another concerning symptom of the virus that doctors are spotting.

It’s being referred to as “happy hypoxia” or “silent hypoxia,” and it refers to a phenomenon where people who have low levels of oxygen in their tissues don’t seem to be impacted by what is a dangerous condition. The internet is flooded with reports of happy hypoxics who are checking their phones and chatting with nurses at blood oxygen levels that should cause them to be incredibly sick.

“People have had levels of oxygen saturation that’s so low it has astounded doctors that they have not had symptoms,” Dr. William Schaffner, an infectious disease specialist and professor at the Vanderbilt University School of Medicine, tells Yahoo Life.

But why is this happening and how can you tell if you’re a happy hypoxic? Here’s what you need to know.

What is happy hypoxia, exactly?

Hypoxia is a condition where there are abnormally low levels of oxygen in the body, according to the World Health Organization (WHO). “That’s dangerous,” Schaffner says. “Oxygen is the life force that keeps us all going. We need that oxygen in order to breathe appropriately and to keep all our bodily organs functioning. It’s very critical.”

When the oxygen concentration in the body gets too low, people need to be put on ventilators, Schaffner points out.

There’s no one definition at this point of what, exactly, it means to qualify as a happy hypoxic, Dr. David Cennimo, assistant professor of medicine-pediatrics infectious disease at Rutgers New Jersey Medical School, tells Yahoo Life. “The general consensus is that it’s a state of low oxygen saturation of the blood — hypoxia — without the feeling of shortness of breath,” he says. “Usually, if your oxygen level is low, you would feel some discomfort, shortness of breath and a feeling of not catching your breath. In these cases, people are presenting without complaints.”

“With silent hypoxia, you have a gradual reduction in your ability to exchange gas and take in oxygen,” Dr. Osita Onugha, director of the Surgical Innovation Lab at John Wayne Cancer Institute at Providence Saint John’s Health Center in Santa Monica, Calif., tells Yahoo Life. “Your body is trying to compensate for that reduction in oxygen, but the reduction is so gradual that you don’t notice it. Most people will be short of breath but might not realize it.”

According to the WHO, people are considered hypoxic when they have an oxygen saturation level of 90 percent or below. And according to some reports, some happy hypoxics have had oxygen saturation levels as low as 50 percent.

Why is this happening with COVID-19?

It’s unclear at this point. “One theory is that the hypoxia is due to clots in the small blood vessels in the lungs, which impedes oxygen exchange,” Dr. Richard Watkins, an infectious disease physician in Akron, Ohio, and a professor of internal medicine at Northeast Ohio Medical University, tells Yahoo Life. “There are reports that the hypoxia improves with anticoagulants — medication that dissolves it.”

Your brain is trained to notice when levels of carbon dioxide in your body are too high, but not when your oxygen levels are low, Watkins says. That, he says, could help explain why some people can have hypoxia and not realize it.

Is there any way to know if you have happy hypoxia?

Up to 25 percent of people with COVID-19 may not know they have the virus, Dr. Robert Redfield, director of the Centers for Disease Control and Prevention (CDC), told NPR in late March. And, of those, some may have happy hypoxia.

That raises a huge question: How can you know if you’re one of them? It’s likely that people who have happy hypoxia have some symptoms of the condition — they just don’t realize it, Cennimo says. “If you really watch them for a few minutes, you will also notice that many are breathing fast,” he says. “This increase in respiratory rate is trying to compensate.”

At rest, most people breathe 10 to 12 times a minute, Cennimo says, although it’s considered normal to breathe up to 20 times a minute — it just might feel odd. “Many of these happy hypoxic COVID patients are breathing 20 to 30 times a minute. The strange thing is they do not feel winded, like they just ran a race.” To try to see if you might have happy hypoxia, he recommends counting your breathing over the course of a minute to see how often you’re breathing in.

Another easy test, per Schaffner: Try to exert yourself with something you’d normally do, like walking quickly up stairs or going for a jog. If you have happy hypoxia, you’d feel winded quickly, he says.

You can also use a device known as a pulse oximeter, which measures the oxygen saturation in your blood, Schaffner says. However, he recommends doing the exertion test first. “It’s easier and cheaper and probably about as effective,” he says. “If you exert yourself in any way and you’re short of breath, get that attended to.”

If you’re concerned that you might have happy hypoxia, or if you just aren’t feeling right, Schaffner says, it’s a good idea to call your doctor. They should be able to guide you on next steps.

For the latest coronavirus news and updates, follow along at https://news.yahoo.com/coronavirus. According to experts, people over 60 and those who are immunocompromised continue to be the most at risk. If you have questions, please reference the CDC’s and WHO’s resource guides.

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