See a more readable intro to these ideas on Medium.
This article aims to explain relevant mechanics of breathing and viral reproduction that when combined, lead to a novel model for how conscious breath control can be effective in limiting amount and duration of viral exposure, and why that matters for reducing the spread of an airborne virus.
We can reduce the spread of any airborne virus by helping people develop an intuitive visual understanding of the way viral particles in the air behave. Developing this knowledge will inevitably lead to safer choices, resulting in less viral transmission. The reduction in viral replication rate is limited only by our ability to produce increasingly accurate models of viral particle dynamics, and communicate them efficiently to the people we interact with, and the community at large.
What happens when you breathe? Air is moving in and out of your lungs as a result of a pressure gradient. You can control this pressure gradient with your mind. If you lower your diaphragm, you will expand your lungs—leading to a lower density of air particles in your lungs, creating negative pressure, thus inviting the atmosphere inside of you. We call this process inhalation.
Conversely, raising your diaphragm will contract your lungs and create more pressure, as all the air particles inside your lungs become tightly packed together and bounce off each other more. Then, the higher pressure within your lungs compared to the relatively lower pressure in the atmosphere, will naturally result in an exhalation.
Thirdly, it’s possible for you to close your throat. What’s happening here is that you’re using a flap of muscle called the epiglottis to block the pathway to your windpipe, or larynx. This effectively isolates the container—your lungs—from the outside world, or atmosphere. If your epiglottis is healthy, it can work as a valve to prevent the flow of air in or out of your lungs, without too much concern for the state of the pressure gradient. This is called holding your breath.
To explain viruses, we first introduce the Central Dogma of Molecular Biology. This dogma relates three essential biological concepts: DNA, RNA and proteins.
DNA is a genetic code that contains information about various processes of life in your body. Because each cell in your body only has one copy of your DNA, there’s a process for copying your DNA sequences, or genes, into RNA sequences, and then replicating that RNA many times over.
Now that there are many copies of the same RNA sequence, those copies can themselves be used many times over, simultaneously, effectively increasing the bandwidth for the encoded message within the sequence, and eliminating bottlenecks that would otherwise prevent their use.
Then, we translate these RNA sequences into proteins. Proteins, or enzymes, are little biological machines that go around performing all the processes of life inside your body. Translation is itself performed by protein machines that know how to interpret the genetic codes of an RNA sequence, and assemble together the right amino acid sequence necessary to make various kinds of protein machines needed for the processes of life. The newly synthesized chains of amino acids then fold themselves into the right shape according to the laws of nature.
Viruses work by hijacking the Central Dogma of Molecular Biology. An example viral particle might consist of an RNA sequence, wrapped in a protective coating membrane, with an injector (or spike) that is designed to attach to a receptor. Receptors are a type of protein that straddles the inside and outside of your cell membranes, where they wait to receive particles of a certain shape. When the receptor recognizes the right shape, this triggers some action within the cell. For the purpose of a virus, this action is injecting the viral RNA into your cell.
You may appreciate that if these vulnerable cells are in your lungs, for example, there is some probability that you will inhale a number of viral particles. Then there is some chance that one, or some, of these particles will bounce around inside your lungs and may successfully orient and attach themselves to your vulnerable receptors. At this point, the virus will inject its RNA sequence inside your cell, by hijacking the receptor.
Now, suddenly, there is a foreign RNA sequence inside one of your cells. Cells do not necessarily have a direct way to determine if the RNA sequences floating within them are foreign (possibly enemy) or domestic (likely friendly). Thus the mechanisms responsible for translating RNA sequences into protein machines will simply blindly do so, for both your own RNA, that was originally copied from your DNA, and for foreign RNA, sourced from the virus.
Your fundamental cellular hardware has been hijacked, and is now a factory for producing all the proteins of the virus that are encoded in its RNA. This includes all the components of the viral particles—protective coating membrane, injector, and of course, the RNA sequence. They then assemble themselves into individual viral particles, according to the laws of nature.
Many viral particles are now forming inside your cell, to the point where it’s full of virus. At some point, the cell will become overstretched, and burst open, in a process known as lysing. Now there are viral particles floating about all over the place inside your lungs, possibly attaching to other vulnerable receptors, and repeating the same process, exponentially, ad nauseam.
The virus may spread into the bloodstream, and find the right receptors to hijack elsewhere in the body, attacking other organs.
Cells make up tissues, and tissues are organized into organs (ears, eyes, nose, throat, heart, liver, lungs, skin, etc). If you damage enough of your cells–tissues–organs, the processes of life will no longer be able to sustain themselves. You die.
You have various immune mechanisms for dealing with invading foreign particles. The most relevant mechanism in this case is coughing. The lungs determine that they have a source of irritation, and seek to expel it. This results in a cough—a rapid exhalation mediated by the valve of the epiglottis. If the foreign particles are relatively benign, e.g. pollen or some other irritant, all is well. However, if you have the unfortunate fate of being infected with a virus, the cough mechanism will be hijacked by the viral particles to increase their spread. There are now viral particles all around you, being potentially breathed in by those close to you, landing on surfaces, etc.
You may now appreciate that coughing is a special case of breathing. So of course, when you are breathing normally, you may be exhaling viral particles into the air if you are infected, even if you do not have a cough. People who are infected with the virus but do not have symptoms such as coughing are called asymptomatic, but may still be perfectly capable of spreading the virus.
Let’s explore the implications for human behavior. When you are in a room, hallway or elevator, you are in an enclosed space, sharing the available atmosphere with the people around you. Anyone, including yourself, may be infected with an airborne virus and be unaware, due to a lack of symptoms. This is primetime for viral spread.
Take a breath before you enter the room, or elevator. When inside, tend towards a slow and gentle exhale. You’ll appreciate that it’s near impossible to get infected unless you allow the atmosphere to flow into your lungs. Conversely, this would be a bad time to sharply exhale, as you yourself may be unknowingly infected, and could potentially be ejecting viral particles into the atmosphere you’re sharing with the people around you.
On the other hand, when you’re in public and find yourself away from other people, you have a good opportunity to breathe. Minimize your breathing as you reach near other people at the store. Or, if time allows, you can wait for the space to clear. You can always consider in the back of your mind how the distance between you and others, along with your breathing patterns, influence the risk of spreading infection.
You might also be wary of stepping into a space immediately after someone else. Imagine a concentrated cloud of viral particles that could potentially be around the person as they breathed, slowly dispersing away, while some of the particles fall to the ground. You might wait a moment for the air to clear.
How quickly you are moving will also increase the amount of energy, and therefore oxygen you need, resulting in harder breathing. A casual stroll instead of the usual brisk walk might be more neighborly to those around you. Similarly, loudly talking, laughing, singing and yodeling are probably best left for after you’re out of the elevator.
Consider how the number of viral particles that make it into your lungs, or viral load, impacts the likelihood of getting infected at all. More viral particles bouncing around in your lungs means a greater chance of one of them lining themselves up correctly in orientation and space, to attach to the right kind of receptor. Even if you have to breathe possibly viral air, breathing in less air would be better.
As we return to normal life, there are still precautions you can take in social settings where you decide wearing a mask isn’t reasonable or convenient. For example, at a bar or a show, you might be maskless, talking closely with some friends. You could take your scarf or a napkin and cover your mouth as you move around the venue, to reduce the chance of cross-contaminating your group with other groups.
While none of these are a slam dunk on their own, you can see it’s a probability game. Just do the best you can muster, try to improve your understanding, and don’t sweat it when you mess up. Safer breathing is a skill you can develop. Hopefully you can see how breathing mindfully without a mask can be safer than breathing mindlessly with one.
Holding your breath is also an option, although you’ll find it uncomfortable at first due to the CO2 buildup. Holding your breath is also a learnable skill.
We can synthetically extend our immune system by wearing masks, to further disrupt the flow of the rather large viral particles by hoping they will become entangled in the mask material, or not spread as broadly when we breathe. But even if you don’t have your mask with you or can’t wear one, even in the future when a new viral threat emerges, you can always wear the mask of the mind.