DNA Explainer: What is Happy Hypoxia and how is it a 'silent' killer in COVID patients

As the second wave of the Covid-19 pandemic rages, young people are now reporting severe lung infections and "unpredictable" symptoms. The latest to join the long list of COVID-19 symptoms is 'happy hypoxia' which means very low levels of oxygen in the blood.

This condition is leaving medical professionals across the world baffled. According to ScienceMag, 'this one seems to defy basic biology'. Patients infected with the virus, with extremely low blood-oxygen levels are as comfortable as one can be with an illness, are scrolling on their phones, and talking to doctors normally. Clinicians have called them 'happy hypoxics'.

What is Happy Hypoxia?

Hypoxia refers to very low oxygen levels in the blood. The normal oxygen saturation in the bloodstream of a healthy person is above 95%, but COVID-19 patients display dangerous declines of as little as 40%.

While hypoxia is a warning signal for imminent failure of vital body organs like the kidneys, brain, heart and is usually accompanied by prominent breathlessness, happy hypoxia does not prompt any such obvious external signs. As a result, in the initial stages of sickness, the COVID-19 patient, on the outside, appears to be alright and "happy".

The proper medical term is "silent hypoxia." It happens when people are unaware they are being deprived of oxygen and are therefore showing up to the hospital in much worse health than they realize.

How does this happen?

Doctors speculate that, for some people, Covid-19 lung problems progress in a way that isn't immediately apparent. As patients focus on battling symptoms such as fever and diarrhea, the body begins fighting back against the lack of oxygen by speeding up breathing to compensate.

People may not be aware of their more rapid breathing rate and don't seek help, yet blood oxygen levels continue to fall. In the meantime, the body slowly becomes somewhat adjusted to the lower levels of oxygen, much like what happens when a person travels to a higher altitude.

30% patients who require hospitalisation have happy hypoxia

Speaking to India Today, Dr Rajkamal Choudhry, associate professor at the Department of Medicine of the Jawaharlal Nehru Medical College, Bhagalpur in Bihar said that in some Covid-19 patients experiencing happy hypoxia, oxygen levels have dropped to 20-30 percent. He estimated that 30 percent of India's covid-19 patients who require hospitalisation have happy hypoxia, which could prove fatal.

How to identify happy hypoxia in patients who have mild symptoms?

Besides having the covid-19 symptoms, if a person has happy hypoxia, they might experience ‘change of the colour of lips from natural tone to blue, skin discolouration to red or purple tone or profuse sweating even when not doing arduous physical work could be a symptom of happy hypoxia’, states the India Today report.

Even while portraying only minor symptoms of COVID-19, such as cough, sore throat, fever, headaches, without any perceivable breathing difficulty, it is advised to continuously measure blood oxygen levels using a pulse oximeter.