Covid and Lung Function

A new research report indicates three ways in which Covid can restrict the exchange of oxygen and carbon dioxide that normally occurs in the lungs. Since the beginning of the pandemic, low oxygen levels have been an acute concern. Low levels even for a relatively short period of time can result in organ and especially in brain damage and death. After all, that’s what strangulation is about, isn’t it?

On a pulse oxymeter, normal readings for oxygen levels range between 95% and 100%. Below 92%, readings become a cause of concern and readings in the 80s may prompt use of supplemental oxygen. Readings below 85 may warrant an ER visit. Some Covid patients have had readings below 60.

Through simulation modeling, researchers have identified three ways in which Covid-19 could impact oxygen levels in the bloodstream.

  1. Normally, if a section of a lung is damaged, blood vessels constrict blood flow in that area to force more blood into healthy areas where there is oxygen available. This process may be reversed with Covid, bringing more blood through parts of the lung where no oxygen is available.
  2. Covid may be prompting formation of small blood clots in the lungs, as it does in arteries. The lung clots may be too small to show up on CT or other scans.
  3. By reducing the ability of a lung to fully eject carbon dioxide, Covid may reduce the amount of oxygen entering the lungs. This mismatched “air flow/blood flow” ratio would also reduce oxygen levels.

The net effect is the “silent hypoxia” seen in many Covid patients. In some, oxygen levels have dipped low enough to be “incompatible with life”.

While the first effect could account by itself for the hypoxia seen in patients, the researchers believe that all three effects may be happening.

Now to the interesting part.

One of the treatments for patients with low oxygen levels is resting in bed on the stomach instead of the back.

A number of interventions are currently being studied, including a low-tech intervention called prone positioning that flips patients over onto their stomachs, allowing for the back part of the lungs to pull in more oxygen and evening out the mismatched air-to-blood ratio.

If prone positioning is good for Covid patients, why isn’t it good for others with breathing issues, for smokers, and frankly, for anyone? Who doesn’t need a well-functioning brain?

Healthline offers both pros and cons to the prone sleep position:

  • On the plus side, it can reduce snoring and sleeo apnea
  • On the minus side, it can result in neck and back discomfort, and is totally unsuitable for pregnancy.

However, I’ve not found any thorough research on sleep positions that accounted for differences in body structure and BMI. That would be interesting to see.


  1. Jacob Herrmann, Vitor Mori, Jason H. T. Bates, Béla Suki. Modeling lung perfusion abnormalities to explain early COVID-19 hypoxemia. Nature Communications, 2020; 11 (1) DOI: 10.1038/s41467-020-18672-6
  2. Boston University. “Three reasons why COVID-19 can cause silent hypoxia: Biomedical engineers use computer modeling to investigate low blood oxygen in COVID-19 patients.” ScienceDaily. ScienceDaily, 19 November 2020.


  1. While there are reasons this flipping may not work, I agree that it leaves room for exploring. Out of every dark cloud, a tiny light of sun has the chance to shine through. This may be one of those times.

    Liked by 2 people

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