Study sheds light on explanation for lack of blood oxygenation detected in many COVID-19 patients ANI | Updated: Dec 30, 2020 07:53 IST Washington [US], December 30 (ANI): One of the physiopathological characteristics of COVID-19 that has most baffled the scientific and medical community is what is known as "silent hypoxemia" or "happy hypoxia". A recent study sheds light on the explanation for the lack of blood oxygenationdetected in many COVID-19 patients. The study was published in the journal function. Patients suffering this phenomenon, the causes of which are still unknown, have severe pneumonia with markedly decreased arterial blood oxygen levels (known as hypoxemia). However, they do not report dyspnea (subjective feeling of shortness of breath) or increased breathing rates, which are usually characteristic symptoms of people with hypoxemia from pneumonia or any other cause.