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The navy has extensively studied performance in high CO2 environments on submarines, and found that it has no impact under levels much higher than you're likely

The navy has extensively studied performance in high CO2 environments on submarines, and found that it has no impact under levels much higher than you're likely to get indoors. This study found no impact on decision making at 15000 ppm https://pubmed.ncbi.nlm.nih.gov/29789085/ https://pubmed.ncbi.nlm.nih.gov/29789085/ That's 10x higher than you're likely to be exposed to in a poorly ventilated conference room.

swsieber 6y ago
From the study, emphasis mine: > we were unable to replicate this effect in a submariner population Please don't over-generalize paper results.
- whatshisface 6y ago
  What's biologically different about submariners? Mostly male, I guess, but anything else?
  - dmoy 6y ago
    Physically more fit, pass certain psych screenings, etc. It's not exactly a good random sampling, they filter candidates very aggressively.
    - learc83 6y ago
      It's not a good random sample, but they were exposed to C02 levels 10x higher than what you'd be exposed to even in a poorly ventilated conference room.
      - loopz 6y ago
        Were they exposed to out in the woods situations with conflicting goals and outcomes, or mainly just following routine and script?
        deleted 6y ago
        [deleted]
        learc83 6y ago
        The used the same kind of decision making skills test that the tests that showed cognitive decline due to CO2 used.
  - tfehring 6y ago
    Possibly "tolerance" to high levels of CO2, and/or a baseline level of cognitive performance that's already impacted by chronic exposure to high levels of CO2?
    - learc83 6y ago
      Studies that raised the alarm on C02 levels showed a severe impact on cognitive function at 1,500ppm. Submariners routinely live and work in levels at 5,000ppm. >baseline level of cognitive performance that's already impacted by chronic exposure to high levels of CO2 If that explanation is true submariners would barley be capable of operating their boats. >Possibly "tolerance" to high levels of CO2, And if that explanation is true new submariners would be barely functional. The most likely explanation is that the study that showed severe impairment at relatively low levels is wrong.
      - maxbond 6y ago
        > Submariners routinely live and work in levels at 5,000ppm. People are telling you that this study may not be reflective of the general population, and you are only demonstrating their point. It seems like you are really invested in a particular outcome for this research. Maybe you should take a step back and try to let go of your biases. Dying on the hill of one particular study is the definition of cherrypicking.
        marchenko 6y ago
        I think the poster has a good point. It's not just the one submariner study he's referencing that's relevant, it's the decades of experience navies of various nations have operating submarine fleets - the armed forces are not shy about collecting physiological data in the service of operational readiness. If the headline article is correct, we should be very concerned that a significant fraction of the world's nuclear weapons are immediately operated by officers experiencing extraordinary CO2 exposure. Every submariner is green at some point (and there are female submariners as well) - how is acclimation handled?
- learc83 6y ago
  They were exposed to C02 levels 10x higher than what you'd be exposed to even in a poorly ventilated conference room. It's likely that this mitigates any biological differences. Nothing is certain, but that study combined with the fact that submariners have been operating for months at at time with C02 levels up to 5,000ppm and no one has ever noticed a problem says that studies showing a severe impact at 1,500ppm are probably wrong.
  - AtlasBarfed 6y ago
    Well, what was the 02 concentration? Did they just change the CO2 and N2 relative concentrations while keeping the O2 normal? Not that I have detailed knowledge the implications of N2 vs CO2 on O2 uptake. I could be wrong, but I would think the CO2 increase comes at an O2 loss. While there is about 20% of O2 in the atmosphere, and <1% CO2, but it only takes .2% of O2 --> CO2 to drop the relative concentration of oxygen by 1 percent, which should be noticeable, especially the more out of shape you are. Naval seamen are also in a lot better shape, so they aren't on the borderline of O2 uptake (like a lot of the most vulnerable COVID-19 people). The general population is much more out of shape.
    - learc83 6y ago
      The effects people are worried about are at 1k to 2k ppm. Even assuming CO2 is displacing O2 only, the drop in O2 levels is less than the change in about 100ft of elevation. Since oxygen only accounts for about 1/5 of the displaced gasses, you're talking about a difference in about 20 ft of elevation. Not enough to notice even for horribly out of shape people, and definitely not enough to cause the kind of effects reported.
    - Tagbert 6y ago
      Have you been to Denver? Changing altitude has a greater than 1% change in O2 available. You feel it initially but quickly adapt and don’t tell them they are cognitively impaired. :)
- floatingatoll 6y ago
  Were the submariners fresh recruits or long-time personnel practiced at (acclimated to) operating in a high-CO2 environment? Is a submarine’s ratio of O2 to CO2 maintained at a normal fresh air ratio at its higher absolute CO2 level? etc.
- tree3 6y ago
  Please don't dismiss results just because they aren't 100% descriptive of the normal population.
mleonhard 6y ago
There is a lot of variation in humans. I believe that some people can easily handle CO2 while others get panic attacks. That study, of CO2 effects on submariners, suffers from selection bias. Here's a US Navy presentation from 2003 that indicates that 10% of submariners quit during their first assignment for psychological reasons: http://annex.ipacweb.org/library/conf/03/bing.pdf http://annex.ipacweb.org/library/conf/03/bing.pdf I believe many of those people quit because they experience anxiety or other negative effects from moderate CO2 levels. Many others never apply to the submarine service in the first place because they have experienced CO2-triggered anxiety which they believe is claustrophobia. Some anecdata: https://www.reddit.com/r/newtothenavy/comments/439j6f/for_prospective_submariners_how_do_they_test_for/ https://www.reddit.com/r/newtothenavy/comments/439j6f/for_pr... Apparently prospective astronauts must pass a CO2 tolerance test: https://www.forbes.com/sites/quora/2016/02/05/could-you-pass-the-quirky-claustrophobia-test-nasa-gives-to-astronauts/#2e0c15dd26b4 https://www.forbes.com/sites/quora/2016/02/05/could-you-pass... EDIT: Submariners get several CO2 tolerance exams, as reported on Quora: > At Basic Enlisted SubSchool (BESS) you are tasked with quite a few things that test you for claustrophobia. The old Ascent tank (to practice submarine emergency escapes I understand that is is no longer used) had air locks where you would crowd and entire class into the chamber (in Navy terms 'nut to butt'), and pressurize it so you could open the hatch into the tank and then free ascent (in a Stankehood) to the surface. Lots of fun, washed out a few who couldn't deal with the air lock. > Later in the training they piled us all into a decompression tank and took us to atmospheric pressure equaling some depth or other (it's been a while... almost 40 years) and then they keep an eye on you. > In theory, it's to see if you can handle the air pressure... during the long wait (more than three hours,) due to having the Midnight to 6 AM watch in one of the admin buildings the night before I dozed off. The instructors woke me up when they cracked the hatch and let people out. I thought I was in trouble, but they laughed at me and told me that it was really a 'final exam' in detecting claustrophobics... and my falling asleep proved I didn't have it. https://www.quora.com/How-claustrophobic-is-it-to-be-in-a-nuclear-submarine https://www.quora.com/How-claustrophobic-is-it-to-be-in-a-nu...
- learc83 6y ago
  It's very unlikely that there's enough variability that some people can tolerate 10x the amount of C02 with zero effects. But if I'm wrong, you can look to the 3 other studies I linked that weren't submariners. The studies that test C02 in isolation show no effect at common indoor levels (and levels several times higher). Poor ventilation might have an impact on cognition, but it doesn't look like C02 is the cause.

swsieber 6y ago

From the study, emphasis mine: > we were unable to replicate this effect in a submariner population Please don't over-generalize paper results.

whatshisface 6y ago
What's biologically different about submariners? Mostly male, I guess, but anything else?
- dmoy 6y ago
  Physically more fit, pass certain psych screenings, etc. It's not exactly a good random sampling, they filter candidates very aggressively.
  - learc83 6y ago
    It's not a good random sample, but they were exposed to C02 levels 10x higher than what you'd be exposed to even in a poorly ventilated conference room.
    - loopz 6y ago
      Were they exposed to out in the woods situations with conflicting goals and outcomes, or mainly just following routine and script?
      - deleted 6y ago
        [deleted]
      - learc83 6y ago
        The used the same kind of decision making skills test that the tests that showed cognitive decline due to CO2 used.
- tfehring 6y ago
  Possibly "tolerance" to high levels of CO2, and/or a baseline level of cognitive performance that's already impacted by chronic exposure to high levels of CO2?
  - learc83 6y ago
    Studies that raised the alarm on C02 levels showed a severe impact on cognitive function at 1,500ppm. Submariners routinely live and work in levels at 5,000ppm. >baseline level of cognitive performance that's already impacted by chronic exposure to high levels of CO2 If that explanation is true submariners would barley be capable of operating their boats. >Possibly "tolerance" to high levels of CO2, And if that explanation is true new submariners would be barely functional. The most likely explanation is that the study that showed severe impairment at relatively low levels is wrong.
    - maxbond 6y ago
      > Submariners routinely live and work in levels at 5,000ppm. People are telling you that this study may not be reflective of the general population, and you are only demonstrating their point. It seems like you are really invested in a particular outcome for this research. Maybe you should take a step back and try to let go of your biases. Dying on the hill of one particular study is the definition of cherrypicking.
      - marchenko 6y ago
        I think the poster has a good point. It's not just the one submariner study he's referencing that's relevant, it's the decades of experience navies of various nations have operating submarine fleets - the armed forces are not shy about collecting physiological data in the service of operational readiness. If the headline article is correct, we should be very concerned that a significant fraction of the world's nuclear weapons are immediately operated by officers experiencing extraordinary CO2 exposure. Every submariner is green at some point (and there are female submariners as well) - how is acclimation handled?
learc83 6y ago
They were exposed to C02 levels 10x higher than what you'd be exposed to even in a poorly ventilated conference room. It's likely that this mitigates any biological differences. Nothing is certain, but that study combined with the fact that submariners have been operating for months at at time with C02 levels up to 5,000ppm and no one has ever noticed a problem says that studies showing a severe impact at 1,500ppm are probably wrong.
- AtlasBarfed 6y ago
  Well, what was the 02 concentration? Did they just change the CO2 and N2 relative concentrations while keeping the O2 normal? Not that I have detailed knowledge the implications of N2 vs CO2 on O2 uptake. I could be wrong, but I would think the CO2 increase comes at an O2 loss. While there is about 20% of O2 in the atmosphere, and <1% CO2, but it only takes .2% of O2 --> CO2 to drop the relative concentration of oxygen by 1 percent, which should be noticeable, especially the more out of shape you are. Naval seamen are also in a lot better shape, so they aren't on the borderline of O2 uptake (like a lot of the most vulnerable COVID-19 people). The general population is much more out of shape.
  - learc83 6y ago
    The effects people are worried about are at 1k to 2k ppm. Even assuming CO2 is displacing O2 only, the drop in O2 levels is less than the change in about 100ft of elevation. Since oxygen only accounts for about 1/5 of the displaced gasses, you're talking about a difference in about 20 ft of elevation. Not enough to notice even for horribly out of shape people, and definitely not enough to cause the kind of effects reported.
  - Tagbert 6y ago
    Have you been to Denver? Changing altitude has a greater than 1% change in O2 available. You feel it initially but quickly adapt and don’t tell them they are cognitively impaired. :)
floatingatoll 6y ago
Were the submariners fresh recruits or long-time personnel practiced at (acclimated to) operating in a high-CO2 environment? Is a submarine’s ratio of O2 to CO2 maintained at a normal fresh air ratio at its higher absolute CO2 level? etc.
tree3 6y ago
Please don't dismiss results just because they aren't 100% descriptive of the normal population.

mleonhard 6y ago

There is a lot of variation in humans. I believe that some people can easily handle CO2 while others get panic attacks. That study, of CO2 effects on submariners, suffers from selection bias. Here's a US Navy presentation from 2003 that indicates that 10% of submariners quit during their first assignment for psychological reasons: http://annex.ipacweb.org/library/conf/03/bing.pdf http://annex.ipacweb.org/library/conf/03/bing.pdf I believe many of those people quit because they experience anxiety or other negative effects from moderate CO2 levels. Many others never apply to the submarine service in the first place because they have experienced CO2-triggered anxiety which they believe is claustrophobia. Some anecdata: https://www.reddit.com/r/newtothenavy/comments/439j6f/for_prospective_submariners_how_do_they_test_for/ https://www.reddit.com/r/newtothenavy/comments/439j6f/for_pr... Apparently prospective astronauts must pass a CO2 tolerance test: https://www.forbes.com/sites/quora/2016/02/05/could-you-pass-the-quirky-claustrophobia-test-nasa-gives-to-astronauts/#2e0c15dd26b4 https://www.forbes.com/sites/quora/2016/02/05/could-you-pass... EDIT: Submariners get several CO2 tolerance exams, as reported on Quora: > At Basic Enlisted SubSchool (BESS) you are tasked with quite a few things that test you for claustrophobia. The old Ascent tank (to practice submarine emergency escapes I understand that is is no longer used) had air locks where you would crowd and entire class into the chamber (in Navy terms 'nut to butt'), and pressurize it so you could open the hatch into the tank and then free ascent (in a Stankehood) to the surface. Lots of fun, washed out a few who couldn't deal with the air lock. > Later in the training they piled us all into a decompression tank and took us to atmospheric pressure equaling some depth or other (it's been a while... almost 40 years) and then they keep an eye on you. > In theory, it's to see if you can handle the air pressure... during the long wait (more than three hours,) due to having the Midnight to 6 AM watch in one of the admin buildings the night before I dozed off. The instructors woke me up when they cracked the hatch and let people out. I thought I was in trouble, but they laughed at me and told me that it was really a 'final exam' in detecting claustrophobics... and my falling asleep proved I didn't have it. https://www.quora.com/How-claustrophobic-is-it-to-be-in-a-nuclear-submarine https://www.quora.com/How-claustrophobic-is-it-to-be-in-a-nu...

learc83 6y ago
It's very unlikely that there's enough variability that some people can tolerate 10x the amount of C02 with zero effects. But if I'm wrong, you can look to the 3 other studies I linked that weren't submariners. The studies that test C02 in isolation show no effect at common indoor levels (and levels several times higher). Poor ventilation might have an impact on cognition, but it doesn't look like C02 is the cause.