There has been somewhat of a controversy arising over the wearing of mask by the general public to avoid the spread of Covid 19. This piece from Sarah Hoyts’ blog discusses some of the issues.
Ultimately a mask is a filter and any engineer can tell you that filters have a hellish head loss or pressure drop through them. It takes a lot of energy to pull air through a filter. In human being that energy comes from the lungs. Wearing a mask puts strain on the lungs as the person wearing the mask has to breathe harder to pull the air in. For most people, that isn’t a problem. but for some with respiratory issues that can be an issue.
The flips side is how much wearing masks actually helps constrain the spread of the virus. My thinking is, not much. First of all, surgical masks are, as the article said, more or less useless with an airborne virus. Against viruses that live in fluids, they may help for short periods of time, but when you are dealing with an airborne virus, if the seal is not perfect in both directions, the surgical mask is useless.
Cloth masks are better. But they have their limitations and pulling air through them requires that the lungs work harder. That strains the lungs and just may deprive the body of oxygen. This article goes into rather large detail about some of the hazard of wearing masks for long periods of time.
There is a difference between the N95 respirator mask and the surgical mask (cloth or paper mask) in terms of side effects. The N95 mask, which filters out 95% of particles with a median diameter >0.3 µm2 , because it impairs respiratory exchange (breathing) to a greater degree than a soft mask, and is more often associated with headaches. In one such study, researchers surveyed 212 healthcare workers (47 males and 165 females) asking about presence of headaches with N95 mask use, duration of the headaches, type of headaches and if the person had preexisting headaches.2
They found that about a third of the workers developed headaches with use of the mask, most had preexisting headaches that were worsened by the mask wearing, and 60% required pain medications for relief. As to the cause of the headaches, while straps and pressure from the mask could be causative, the bulk of the evidence points toward hypoxia and/or hypercapnia as the cause. That is, a reduction in blood oxygenation (hypoxia) or an elevation in blood C02 (hypercapnia). It is known that the N95 mask, if worn for hours, can reduce blood oxygenation as much as 20%, which can lead to a loss of consciousness, as happened to the hapless fellow driving around alone in his car wearing an N95 mask, causing him to pass out, and to crash his car and sustain injuries. I am sure that we have several cases of elderly individuals or any person with poor lung function passing out, hitting their head. This, of course, can lead to death.
A more recent study involving 159 healthcare workers aged 21 to 35 years of age found that 81% developed headaches from wearing a face mask.3 Some had pre-existing headaches that were precipitated by the masks. All felt like the headaches affected their work performance.
Unfortunately, no one is telling the frail elderly and those with lung diseases, such as COPD, emphysema or pulmonary fibrosis, of these dangers when wearing a facial mask of any kind—which can cause a severe worsening of lung function. This also includes lung cancer patients and people having had lung surgery, especially with partial resection or even the removal of a whole lung.
While most agree that the N95 mask can cause significant hypoxia and hypercapnia, another study of surgical masks found significant reductions in blood oxygen as well. In this study, researchers examined the blood oxygen levels in 53 surgeons using an oximeter. They measured blood oxygenation before surgery as well as at the end of surgeries.4 The researchers found that the mask reduced the blood oxygen levels (pa02) significantly. The longer the duration of wearing the mask, the greater the fall in blood oxygen levels.
The importance of these findings is that a drop in oxygen levels (hypoxia) is associated with an impairment in immunity. Studies have shown that hypoxia can inhibit the type of main immune cells used to fight viral infections called the CD4+ T-lymphocyte. This occurs because the hypoxia increases the level of a compound called hypoxia inducible factor-1 (HIF-1), which inhibits T-lymphocytes and stimulates a powerful immune inhibitor cell called the Tregs. . This sets the stage for contracting any infection, including COVID-19 and making the consequences of that infection much graver. In essence, your mask may very well put you at an increased risk of infections and if so, having a much worse outcome.5,6,7
People with cancer, especially if the cancer has spread, will be at a further risk from prolonged hypoxia as the cancer grows best in a microenvironment that is low in oxygen. Low oxygen also promotes inflammation which can promote the growth, invasion and spread of cancers.8,9 Repeated episodes of hypoxia has been proposed as a significant factor in atherosclerosis and hence increases all cardiovascular (heart attacks) and cerebrovascular (strokes) diseases.10
There is another danger to wearing these masks on a daily basis, especially if worn for several hours. When a person is infected with a respiratory virus, they will expel some of the virus with each breath. If they are wearing a mask, especially an N95 mask or other tightly fitting mask, they will be constantly rebreathing the viruses, raising the concentration of the virus in the lungs and the nasal passages. We know that people who have the worst reactions to the coronavirus have the highest concentrations of the virus early on. And this leads to the deadly cytokine storm in a selected number.
The fact is that Covid 19 hasn’t turned out to be the massive killer that the predictions and models said that it should be. I suspect that there are a variety of reasons for this. The biggest one is that more diseases have been spread around faster by rapid global travel. The great plagues of the past were caused by the fact that relatively isolated populations were assaulted by new pathogens. In these days of rapid travel, the typical person is exposed to new pathogens very frequently and human immune systems have adapted to match. That makes it harder for a pathogen to take hold. Of course that also means that people are more likely to have autoimmune diseases, but that is the trade off that our bodies make. As far as virus’s go, we don’t die because we are harder to kill.
The panic over the number of cases pushed by the media is rather pointless. Here’s a dirty little secret. eventually we will all get covid 19. But we probably will not even notice.
As an exercise in public health policy, the things done in response to Covid 19 were a disaster and a failure. I do hope that we can learn to not panic and not use public health policy as a political football and an excuse to shutdown the economy. Millions of people were hurt for things that accomplished nothing.