The Dangers of Silent Hypoxia

Silent hypoxia is an unusual manifestation of hypoxia, low oxygen saturation throughout the body, and it's been revealed as a symptom of COVID-19. Silent hypoxia happens when, for reasons still under examination, the normal cues that tell the body its oxygen levels are low don’t register. This can lead to people having dangerously low oxygen levels and no idea anything is wrong, which can turn deadly without warning. To help avoid this dangerous COVID-19 symptom, keeping track of blood oxygen saturation using a pulse oximeter and closely monitoring symptoms may help, but prevention of COVID-19 may be the only sure way to avoid this complication. 

What Is Silent Hypoxia?

Our bodies need a certain amount of oxygen to function properly. Cleveland Clinic explains that when levels fall too low, the effect is generally revealed by shortness of breath, wheezing, changes in heart rate and other symptoms that clearly indicate something’s wrong. In the case of silent hypoxia, sometimes called “happy hypoxia,” patients experiencing critical oxygen levels may have no idea there’s a problem.

The Causes of Silent Hypoxia

Hypoxia can be the result of numerous conditions, but it’s usually the result of severe asthma, emphysema, COPD, pneumonia or some other source of acute respiratory distress. For reasons doctors still don't fully understand, some COVID-19 patients are suffering oxygen levels that should be causing hypoxia symptoms, only they’re breathing normally and not showing any outward signs that their bodies are in distress. When this happens, oxygen levels can quietly drop to dangerous, even deadly, levels.

According to the American Lung Association, hypoxia usually affects both oxygen and carbon dioxide levels in the body and it’s actually high carbon dioxide levels, not low oxygen, that triggers symptoms. This has led some to theorize that it’s possible COVID-19 affects the lungs in a way that reduces oxygen levels but doesn’t affect the carbon dioxide.

The American Thoracic Society recently published an article that brings other, unrelated health conditions into the fray: A large number of people infected with COVID-19 are seniors and diabetics, and silent hypoxia can occur more commonly in these groups. Another possibility is that COVID-19 is affecting the body’s ability to detect the condition due to some type of neurological involvement.

Monitoring COVID-19 Symptoms for Silent Hypoxia

Patients can get a ballpark figure of blood oxygen levels using a pulse oximeter, although doctors warn that accuracy can vary dramatically depending on how the equipment is used and how sick the patient is. People with darker skin, or those in severe respiratory distress, may have less accurate readings. Regardless of those factors, anyone with a blood oxygen saturation reading of less than 93% should seek immediate medical care. Also, a pulse oximeter shouldn’t replace the regular monitoring of symptoms for those who are ill; patients should see a doctor if anything concerning arises, even if their oxygen levels look good.

Silent hypoxia can strike at any time as a symptom of COVID-19, and because there are no obvious cues, it can turn dangerous without warning. COVID-19 sufferers should be especially mindful of their bodies, keeping tabs on their oxygen readings as a matter of course, or seeing a doctor if they’re concerned about dropping levels. Prevention is the best way to avoid this complication, so keep up the social distancing, stay safe and wear a mask when you leave home, every time, all the time.

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