This is very interesting to me and I never considered that scuba was a link to this. Since the pressure of the dive is what alters the absorption of CO2, do you know how one could correlate the CO2 problem for dives vs being on land and having a lot less pressure? I don't know how to connect "high-pressure/low-temp" CO2 issues with "low-pressure/hi-temp" ones. (since the water is much cooler at depth than surface air)
I want to look into this. There may be some studies that inadvertently put the nails in the mask coffin based on CO2 alone
Yes, if you have a mishap with the regulator not functioning properly, CO2 becomes an issue. Don't confuse this with nitrogen though and the bends. 78% of atmospheric air is nitrogen. Our lungs inhale that amount, but exhales all 78% and ZERO amount is taken into the body. CO2, on the other hand, is only 0.394% (~0.4%) in the atmosphere. Our exhale consist of 10 times that amount (4%). Our lungs are able to discern the difference between O2 and CO2. However, if O2 is lacking and if there is an availability of CO2, our lungs will uptake CO2 and the red blood cells will transport it to all the vital organs in our body. This is very damaging to the organs and brain.
In scuba diving exhalation resistance is the total work of breathing and increases when you exhale through a small purge valve on a mask. That in turn inhibits CO2 elimination which exacerbates almost all hyperbaric maladies. If that doesn’t kill you mask fogging will annoy the devil out of you. Inadequate ventilation when scuba diving results in carbon dioxide build-up. This is from inadequate breathing, a tight wetsuit, overexertion, regulator malfunction, deep diving, and contamination of the air supply with exhaled gases, which often cause a carbon dioxide buildup. Carbon dioxide levels in the blood can increase, causing shortness of breath and sedation, resulting in carbon dioxide toxicity. Also, CO2 build-up causes 'Acidosis', which has been identified to causing cancer. There is many degrees of acidosis. It is essentially altering the bodies PH level that can permanently make an individual more prone to cancer, especially when this is compounded with other environmental factors.
The long term effects is astonishingly bad for the reasons I mentioned above.
This is all fascinating. So, with rebreathers, they scrub the CO2. That tells me that the science has been long proven how important it is to keep CO2 out of the inspiration. Since we don't have rebreathers on masks, what's your take on that assessment? Your insight is going to be golden since you have the experience
I'd like to not get caught up with mechanisms scrubbing CO2. My point was always that breathing your own exhale is not only dangerous, but harmful. The deleterious effects of CO2 is readily evident in the short term, but also in the long term. I'm inclined to believe that water pressure of 1 atm (~30 ft.) and more, as exemplified in scuba diving, produces deadly and obvious deleterious effects. Living above sea level, these deleterious effects are spread out across a longer and wider range of health problems, in which the harmful effect can be immediate or appears in the longer term. For example, brain damage due to CO2 is irreversible and cancer could be triggered years later.
I am mentioning only one aspect of danger in breathing your own exhale. The lungs, trachea, nasal passage and sinuses all act as the first line of defense against microbes. They all act as a filter and have their own mechanisms to rid the body of them. In our exhale itself, the result of these functioning defense mechanisms is realized in every breath we take, in which billions and billions of pathogens and particulates are ejected. A face mask completely hinders this remarkable defense system.
Virologists tell us that entry of viruses in our bodies commonly occur through the eye ducts. As a result, we are taught to not to rub our eyes with our fingers. A face mask will restrict exhale and will escape through the gaps at the outer boundaries of the face mask. It turns out that very little exhale travels through the fabric of the face mask. The majority will travel the path of least resistance and escape through the gaps at the edge of the mask. This is actually referred to as 'jet streams'. Two of these large jet streams are upward and escape directly toward the eyes. Have you ever worn safety glasses with a face mask only to realize very quickly your safety glasses have steamed up? One's exhale containing billions of ejected pathogens is directed straight at the eyes when wearing a face mask. Nature has provided us a very efficient design. There's a very good reason why our noses are pointed downward and away from our eyes. There's a very good reason why our exhale should never be restricted.
(post is archived)