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Epidemiological question for Francois (or someone with similar professional chops)
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as we know, being outside is a big risk abater, that is, all things equal, same density of people (whether dense or sparse) outside is better than inside, and the more you're inside the worse it is because the vector is releasing more of the virus into a discrete closed area. so far so good?

now, beyond this - and this goes to the issue of racing - can i segue to another data point, and bring this into the conversation? i've broken my clavicle twice and each time i also broke ribs. the ribs were the worst. painwise. what they used to do was tape them up, like a mummy, because if you coughed or sneezed the tape would keep your ribs from exanding, which is what hurt so much.

but they stopped doing that, because of the incidence of pneumonia. the act of ventilation was/is a critical piece of one's protection against an airborn pathogen that enters the victim through the lung tissue.

as i piece together these disparate factlets, i wonder if outdoor aerobic exercise is a supercharged way of fending off airborn pathogens, through increased ventilation? is the very act of vigorous ventilation an additional protectant? is it a sort of inoculant that argues in favor of the safety of an event - a group competition - assuming that event engages in other best practices?

Dan Empfield
aka Slowman
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Re: Epidemiological question for Francois (or someone with similar professional chops) [Slowman] [ In reply to ]
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Dan, have you ever heard the statement: true, true and unrelated? The mechanism for decreasing post fracture pneumonia is decreasing the incidence of atelectasis, or an area of lung with poor air exchange. Big deep breaths(and the biggest change in minute ventilation actually comes from increasing rate and not volume) from cardio exercise don’t make much difference compared to normal breaths if there is no area of atelectasis anyway.

So minute ventilation is actually the rub in what you are proposing. Each breath becomes a discrete possible exposure event and with an increased respiratory rate, there are more possible exposure events. Outdoor exercise is tolerated due to physical distancing but there is definitely evidence that the airborne exposure cone is bigger during exercise. So no, I don’t think what you are suggesting has any validity.

Credentials: I’m a physician with a MS in exercise science. Your question was really one of physiology rather than epidemiology, IMHO.
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Re: Epidemiological question for Francois (or someone with similar professional chops) [xterratri] [ In reply to ]
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xterratri wrote:
there is definitely evidence that the airborne exposure cone is bigger during exercise

link? would like to read more about this.

Accelerate3 Coaching https://accelerate3.com/
Moxie Multisport https://www.themoxiemultisport.com/
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Re: Epidemiological question for Francois (or someone with similar professional chops) [xterratri] [ In reply to ]
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Dan, agree with xterratri. Really nicely stated.
Also, it is also unclear what the dispersion of virus while deep breathing from exercise might look like. Anecdotal evidence from spreader events suggest continuous speaking and/or singing may further increase transmission by effect on dispersion profiles.

Like any infection, there is some dependency on the innoculum viral dose. So in general, exercising outdoors is terrific since virus disperses much more readily and inactivates in sunlight (not immediate, but likely in range of several minutes). But would give folks a bit more distance than typical guidelines, since so much is still unknown. Take a look at this provocative (though not definitive) modeling work:
http://www.urbanphysics.net/...0v20_White_Paper.pdf

Also, worth noting since the above modeling work, CDC has updated transmission not only from droplet, but also from airborne virus—ie, smaller sized droplets and particles, which would adversely impact the distancing assumptions.

So still good to generously distance while exercising/training outdoors.
Last edited by: Jae K: Oct 18, 20 11:19
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Re: Epidemiological question for Francois (or someone with similar professional chops) [xterratri] [ In reply to ]
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thank you. don't get me wrong. i'm not trying trying to find justification for happy talk. just, are you saying what you're saying because it's intuitive to you? or because there is data based on well-engineered study? some stuff is just inherently hard or impossible to study. if i could use an absurd example, what is more likely to give you a good outcome, falling 3 stories and landing on your back or your stomach? while that is absurd, i ask myself what a study would look like that actually tests whether somebody outside, who engages in (say) a field trial on a bicycle for an hour is more or less likely to catch a particular airborne pathogen versus someone sitting in a chair outside for an hour? where is that test? what would that test look like?

Dan Empfield
aka Slowman
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Re: Epidemiological question for Francois (or someone with similar professional chops) [Slowman] [ In reply to ]
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In general with physical distancing either scenario would be safe- sitting in a chair or riding a time trial. The caveat is that physical exercise affects cortisol levels that can affect immune response. There is definitely an immune suppression effect from a hard effort such as running a marathon. That is well studied, what isn’t well studied is the threshold of effort that tips over to immune suppression and the answer is that it probably is dependent on a whole bunch of factors for an individual.

There are studies that some physical exercise is protective in general for illness but no one has explicitly studied Covid 19 and exercise that I’ve seen yet in the manner you are asking. Probably because of bigger fish to fry. We care a lot about endurance sports but most people do not. Sad panda
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Re: Epidemiological question for Francois (or someone with similar professional chops) [xterratri] [ In reply to ]
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It might be interesting to consider that it's not necessarily the race that lowers the immune response in a competitor.

Most of the serious racers are well into double digit hours on a weekly basis, with multiple efforts above various threshold levels. Heck, if there is one common boast on here it's just that. The race will be run at lower levels of effort, but the training in advance may well have lowered the immune response in the individual to the point where in a large crowd of untested individuals racing or supporting, they have become more susceptible than a weekend warrior..

I offer not a single fact as evidence, and no professional chops whatsoever, other than the somewhat accepted fact that at peak fitness, we are not necessarily at peak immunity.
Last edited by: michael Hatch: Oct 20, 20 13:15
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Re: Epidemiological question for Francois (or someone with similar professional chops) [Slowman] [ In reply to ]
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Slowman wrote:
thank you. don't get me wrong. i'm not trying trying to find justification for happy talk. just, are you saying what you're saying because it's intuitive to you? or because there is data based on well-engineered study? some stuff is just inherently hard or impossible to study. if i could use an absurd example, what is more likely to give you a good outcome, falling 3 stories and landing on your back or your stomach? while that is absurd, i ask myself what a study would look like that actually tests whether somebody outside, who engages in (say) a field trial on a bicycle for an hour is more or less likely to catch a particular airborne pathogen versus someone sitting in a chair outside for an hour? where is that test? what would that test look like?

Well i can answer what happens when you fall, end up on your back with one arm and one leg under a bus but no road rash on face because you are on your back. I am yet to try the fall on your stomach version of your test. I'll let you know how that shakes out, but the fall was from a bike, not from three stories. We could put someone on a set of rollers on the third floor and launch them out the window after they smash thru the glass if we can get him to rev up a heavy enough wheel. But he'll need a gymnast to make sure they do enough pirouettes to land on back. I think this study is doable, just need sign ups.
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Re: Epidemiological question for Francois (or someone with similar professional chops) [xterratri] [ In reply to ]
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i considered the immune suppression that happens after a hard effort. that is a modifier, but i think once we go down that road we introduce a variable that's outside the circumscription of this question. if i run a 5k race, how compromised is my immune system from that effort? once we leap to the assumption that we're talking about a person who's overtraining, and racing in an ironman, that adds a level of complexity to the question.

let me stipulate that you obviously know a ton more than i do about this. but the questions i have refer to statements like these: "definitely evidence that the airborne exposure cone is bigger during exercise." what i read in that, at face value, is that the very act of increased ventilation shovels into the lungs more of what's in the air. we're obviously inhaling a lot more particulate matter, smog, smoke, and it appears a known thing that this contraindicated when there's a lot of smoke and smog. do we know that the same thing is true of pathogens?

i ask because what i find is that moderate exercise, in my experience, also does the opposite: it appears to clear the lungs. at least my lungs.

hence my wondering about this.

Dan Empfield
aka Slowman
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Re: Epidemiological question for Francois (or someone with similar professional chops) [Slowman] [ In reply to ]
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I read the "definitely evidence that the airborne exposure cone is bigger during exercise" as meaning the racer would be shovelling OUT more (potentially infected) air into the atmosphere - not about the next person sucking more in.

And by extention, more likely to then be sucked into the next passing athlete. Though this may be a double whammy - more blown out ny Infected person A, AND more sucked in by previously-negative person B.

Although if the hard-breathing athlete is blowing the disease out over a wider volume, the risk profile must be complicated by the different "germ-density". And whilst I'm not an MD, I'd find it hard to believe it will be a linear relationship. It's going to be much more complicated!
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Re: Epidemiological question for Francois (or someone with similar professional chops) [BobAjobb] [ In reply to ]
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BobAjobb wrote:
I read the "definitely evidence that the airborne exposure cone is bigger during exercise" as meaning the racer would be shovelling OUT more (potentially infected) air into the atmosphere - not about the next person sucking more in.

And by extention, more likely to then be sucked into the next passing athlete. Though this may be a double whammy - more blown out ny Infected person A, AND more sucked in by previously-negative person B.

Although if the hard-breathing athlete is blowing the disease out over a wider volume, the risk profile must be complicated by the different "germ-density". And whilst I'm not an MD, I'd find it hard to believe it will be a linear relationship. It's going to be much more complicated!

interesting, because you and i came to very different conclusions as to what that phrase meant.

when i used to have my factory, in san diego, i would suffer, fairly regularly, from whatever was in the "marine layer" that hugs the california coast and, i would guess, most coastlines. and would begin to feal sort of fluey. i would take my bike, drive up to julian, in the mountains east of san diego, clean air, dry, higher altitude, and ride for a couple of days. the first ride i would cough a lot. but i'd feel better even during that first ride. after 2 or 3 days i felt like a million bucks.

experiences like that shape my intuition about this. but it's only intuition, and not science, and that's an anecdote that may speak to certain elements of lung function, but may not apply at all to pathogens.

Dan Empfield
aka Slowman
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Re: Epidemiological question for Francois (or someone with similar professional chops) [Slowman] [ In reply to ]
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Caveat, I'm not an expert in immunology, but in infectious disease. Though, I have brushed up on immunology since COVID (e.g. cytokine storm, vaccine, etc.).

Here's a paper that reviews some of the current literature on exercise and our immune system. https://www.tandfonline.com/...744666X.2019.1548933

Conclusion is we don't really know if it has a negative affect on immunity. All we know is exercise of various forms alter/trigger parts of the immune system.

One example paper brings up are the studies have confounding variables and questionable methods/metrics. Are infections due to mass gatherings at an event? What about travel and related stress? How is infection defined? Symptoms is a cheap and easy metric but not very specific.

Dan, you bring up a very valid point that I haven't even thought about regarding inspiration. We've been mostly focused on expiration (choir singing, korean gym contact tracing and most recently Canadian indoor spin class). I suspect heavy expiration and aerosolizing the particles contribute more to infection (unless you have some chronic lung disease like COPD).
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Re: Epidemiological question for Francois (or someone with similar professional chops) [Jae K] [ In reply to ]
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So help me out here. A respiratory droplet is about 5-10 nm. A covid virus particle is about 0.1-0.5 nm. Assuming that the viral load is the determining factor in whether you get infected or not, how likely is it that enough of a 0.1-0.5 nm particle would actually make it into your nasal passages while running by an infected individual at 7-8mph? The physics don't seem to hold up here.

Next races on the schedule: lolwut?
Last edited by: alex_korr: Oct 18, 20 20:22
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Re: Epidemiological question for Francois (or someone with similar professional chops) [Slowman] [ In reply to ]
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As someone else said what you want to avoid in a rib fracture pt is areas of atelectasis. That is areas of lung that are collapsing because they are not ventilating. They are good places for bacteria to breed. But increasing ventilation beyond that needed to keep the lungs inflated likely does not add any extra protection. How you would study that no idea.

They constantly try to escape from the darkness outside and within
Dreaming of systems so perfect that no one will need to be good T.S. Eliot

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Re: Epidemiological question for Francois (or someone with similar professional chops) [alex_korr] [ In reply to ]
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Based on documented cases, extremely low. I don't know of any document case of outdoor transmission from exercise.

We know outdoor transmission happens, but documented cases are from close and possibly prolonged contact. In spring there was an outbreak from an outdoor church service. The church is Pentecostal and well there's a lot of close physical contact (I know since I used to go to one). Recently, ACB announcement and subsequent outbreak (plenty of video showing close prolonged contact). I was just consulted to see a COVID pt who went to a funeral of ~200 people. They masked inside but not outside.

There's so much dilution from being outside. Also contact time is extremely short. I'm sure there's someone here with more knowledge on fluid dynamics that can chime in (I only know a little from my first 2 years of college being a chem e major before i switched).
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Re: Epidemiological question for Francois (or someone with similar professional chops) [alex_korr] [ In reply to ]
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I understand the desire to understand the transmission characteristics of this virus. To be completely transparent, this is not my area of expertise. I am a physician, a clinical trialist, and even previously led the investigation of a SARS-CoV-2 investigational drug, and familiar enough with epidemiology to have led numerous epidemiology efforts in the past (though not specifically with COVID-19).

Experimental studies have shown aerosolized virus, after hours in the air, can be recovered with replication-competent SARS-CoV-2 virus. There is quite a bit of physics and airflow simulation data out there that I can cite below from the WHO, but again, this is not my area of expertise. But in totality raise more concerns for judicious caution in light of that uncertainty than being overly cavalier about distancing.

I love this sport, and am a huge advocate of exercising and training outdoors amid this pandemic. I love that we triathletes love to “science” the heck out of things to buy a sum of marginal gains. With regard to this pandemic, safety can be also be increased by incremental sums of risk-reducing behavior.

In the past, I have more than once been hit by a droplet/ globule running or riding behind or past someone—before it was just gross, but now consequences can be more significant. The medium-sized droplet can carry thousands of replication-competent virus. Can there be danger from inhaling a cloud of aerosolized virus outside? The risk is likely lower, but also non-zero.

These words we share in public forums matter, since they can impact individual behavior and risk tolerance.
If the objective of what you are saying is to not distance while outdoors, I would disagree with you.
These are the early days of SARS-CoV-2, and objectively little is known about this virus, except to say this is highly contagious, morbid, and has killed hundreds of thousands of Americans. The available data suggest we should continue to distance even when exercising outdoors. If we expend a few extra joules giving people a wide berth, or extra watts distancing and not drafting on a training ride, what is the down side except a better workout?

Dan,
WRT experimental evidence. I would be cautious in making any parallels between avoidance of atelectasis and SARS-CoV-2 transmission. These are 2 entirely different things as many others here have commented. If anything, deep breathing likely increases chances for infection. If you want want quantitative metrics, deep breathing increases volume of air being brought into the lungs (ventilation). Gas exchange is measured in exercise labs all the time, and can be an easy surrogate for inhaled particles.

Mittal R, Ni R, Seo J-H. The flow physics of COVID-19. J Fluid Mech. 2020;894.
Bourouiba L. Turbulent Gas Clouds and Respiratory Pathogen Emissions: Potential Implications for Reducing Transmission of COVID-19. JAMA. 2020;323(18):1837-1838..
Asadi S, Bouvier N, Wexler AS, Ristenpart WD. The coronavirus pandemic and aerosols: Does COVID-19 transmit via expiratory particles? Aerosol Sci Technol. 2020;54:635-8.
Morawska L, Cao J. Airborne transmission of SARS-CoV-2: The world should face the reality. Environ Int. 2020;139:105730.
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Re: Epidemiological question for Francois (or someone with similar professional chops) [hubcaps] [ In reply to ]
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So much of how this disease is transmitted is unknown, I think you have to look at real world observation. If Covid was easily transmittable outside, recent protests and civil unrest would have been super-spreader events....people in close proximity to one another, chanting, singing....etc. As far as I have seen, there were no increases in transmission rates among protestors.

My second observation from living in San Francisco, early on there was a lot of concern about transmission among the homeless population, many of whom are immuno-surpressed. So far in SF there is one confirmed Covid death amongst the homeless population.

So, I hypothesize that if you aren't seeing huge infection rates with protestors or homeless, it seems to be very unlikely that you will catch this during outdoor exercise.
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Re: Epidemiological question for Francois (or someone with similar professional chops) [Jae K] [ In reply to ]
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Jae K wrote:
If the objective of what you are saying is to not distance while outdoors, I would disagree with you.

if that were my objective, you would be right to disagree with me. if you want to know my posture on this, i think i state it pretty clearly in my prelude to the first-person account of IM AZ 70.3, reachable via our front page.

i think IM did an outstanding job of making sure its participants distanced while outdoors. i would feel a lot safer doing that race, i think, than i feel when i shop at costco.

that said, i have reservations about 2x or 3x that number of competitors, as may be the case in florida. i'm awaiting what that will look like. i also have concerns about what competitors do when off the footprint of the race. if i were ironman, i would make the violation of social distance rules an auto-DQ, whether on the footprint or not, just as the NBA did when its players were in the bubble. but i don't think IM is going to do that.

further, IM has a unique capacity to "contact trace", for lack of a better term, its contestants, to see what the outcome is. i think if we knew how things went for people who raced IM AZ 70.3, in 3 or 4 weeks, we'd know if this was a success or not. we have the capacity to make science, where there is no scientific consensus, if we had the nerve and the will to chance a result that we might not like.

Dan Empfield
aka Slowman
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Re: Epidemiological question for Francois (or someone with similar professional chops) [Slowman] [ In reply to ]
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Slowman wrote:
Jae K wrote:
If the objective of what you are saying is to not distance while outdoors, I would disagree with you.


if that were my objective, you would be right to disagree with me. if you want to know my posture on this, i think i state it pretty clearly in my prelude to the first-person account of IM AZ 70.3, reachable via our front page.

Hi Dan,
I think you mistook my disagreement--it was a reply to another respondent and not you.

But I did read your prelude, which was thoughtfully written. Nice article! By the looks of the article and IM Safe Return to Racing Event Guidelines, I applaud the IM organization for an excellent set of guidelines and for the methods deployed in the execution of its "proof-of-concept" pilot event; however, I do not believe the timing was prudent.

The Subject Header reads "Epidemiological" question, which is the study of disease in populations and not just individuals, something I know a little about. The US and much of the globe is in the midst of a COVID-19 surge during a period when it is critical to control spread for public health, ie before winter and flu season, when clinical manifestations are confounded, spread is increased from indoor contacts, and health systems more stressed. Irrespective of the care IM might have taken with the event itself, the country is in the midst of a growing pandemic surge including Arizona, with had an increase from ~<400 daily cases of COVID a few weeks ago to nearing almost ~1000 cases daily (~100% increase), most of which was in Maricopa County where the IM event occurred. The increase in cases in Maricopa county is most likely due to inadequate safety and distancing behaviors endemic to the region. Not only will the IM event be difficult to exonerate from any contribution to adverse regional trends, the event itself is drawn from the participation of national and international participants traveling through airports, transportation, contacts, from and through regions likely experiencing disease surges themselves, participating in an event with a density of interactions of traveling athletes, local residents, shops, restaurants, hotels, etc. Arizona also has permissive regional practices with no travel restrictions for out-of-state visitors. I believe it is extraordinarily unlikely for the IM event be a super-spreader, but can the event facilitate spread of COVID in totality of off-course and on-course interactions by virtue of having taken place? I think possible to probable.

As I have stated in the other thread, I am generally not concerned about the effects of COVID on athletes, who are likely to have only mild to moderate symptoms (although severe manifestations have been observed in some). But rather athletes can be vectors for transmission, even while asymptomatic, to vulnerable members of society for whom this disease can be deadly. Never before has the fate of vulnerable people been so much at the mercy of behaviors of others. Sorry for the length of these responses, I have spent way more time than i should, but if even one serious outcome can be averted it would have been worth it.

Also, given micro- and macro-population trends in COVID-19, impact of the IM event is likely to be highly confounded and difficult to interpret--and likely background trends in Maricopa County unfavorable for the IM event. I agree with you the IM organization would be well-served by getting information from every volunteer and participant 2-3 weeks after the event for signs an symptoms of COVID to demonstrate no unfavorable impact on public health.

I love triathlon, even though I am so mediocre at it. And I am as eager as anyone to start racing again!
And I want to see the sport thrive, as well as see the Ironman Organization flourish.
Poor timing of elective national/international events, categorically deemed higher risk by the CDC, during a pandemic surge at a period critical for public health may tarnish the sport.

Take care, and wishing everyone well.
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Re: Epidemiological question for Francois (or someone with similar professional chops) [Slowman] [ In reply to ]
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It's a difficult question to answer. Some exercising is good because it improves immune function. But then, too much decreases it. So there is some level of optimization here.
Second, there is a fluid dynamic aspects of virus propagation outdoor vs indoor, and that's not a question I can answer. If static, you're better off outside. That's what the current epi data show.
But if moving, then things get more complex and the answer is probably "it depends".
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Re: Epidemiological question for Francois (or someone with similar professional chops) [Francois] [ In reply to ]
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Recently published, Maximal Exercise Capacity is Inversely Related to Hospitalization Secondary to Coronavirus Disease 2019, concludes that "These data further support the important relationship between cardiorespiratory fitness and health outcomes. Patients should be encouraged to regularly engage in aerobic exercise to maintain or improve their exercise capacity. Future studies are needed to determine if improving exercise capacity is associated with lower risk of complications due to viral infections, such as COVID-19".

STRAVA INSTAGRAM
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Re: Epidemiological question for Francois (or someone with similar professional chops) [Dr. Triax] [ In reply to ]
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That's not really what Slowman is asking though. Yes, having a high VO2max will protect against URI. The question is whether exercising helps on a daily basis for everyone right now, to protect against COVID19.
Which the paper does not answer, and would have to be done prospectively. Further, given the recent evidence of cardiac involvement in many patients with COVID19, I'd be pretty cautious using exercise to as a protection mechanism...
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Re: Epidemiological question for Francois (or someone with similar professional chops) [Francois] [ In reply to ]
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Agree.
I think Dan's question is more about medical physiology than epidemiology.
In the context of respiratory splinting, ie impaired breathing due to injury, there can be associated atelectasis, collapsed airways, which traps mucus and the local microbiome from clearing, fostering pneumonia. The question is whether increased ventilation can ward off COVID-19 infection. Since SARS-CoV-2 is not part of the flora in the lungs, the above rationale is not relevant. Quite the opposite, increased ventilation likely gains a larger surface area and overall increased probability of viral contact with lung epithelia if a certain quantum of viral dose is required for infection.

The discussion about immunity is tough, since so little is known about this novel virus. While intact immune systems are needed to generate protective neutralzing antibodies, over-robust cytokine response can lead to severe outcomes--the effectiveness of dexamthasone for severe COVID-19 supports that argument. Agree the net situation right now is we don't really know.
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Re: Epidemiological question for Francois (or someone with similar professional chops) [Dr. Triax] [ In reply to ]
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Dr. Triax wrote:
Recently published, Maximal Exercise Capacity is Inversely Related to Hospitalization Secondary to Coronavirus Disease 2019, concludes that "These data further support the important relationship between cardiorespiratory fitness and health outcomes. Patients should be encouraged to regularly engage in aerobic exercise to maintain or improve their exercise capacity. Future studies are needed to determine if improving exercise capacity is associated with lower risk of complications due to viral infections, such as COVID-19".

There is so much scientific literature that show "heathy people are more likely to be healthy" and conversely "sick people are more likely to get sicker". ;-)
But really, since most observational research data suggest adverse outcomes are associated with obesity and certain co-morbidities, it serves everyone well to try to stay healthy though regular exercise.

And agree with everyone else here that outdoors is safer than indoors due to combination of greater dispersion of virus, ability to distance better, and quicker inactivation of virus by sunlight. And we should continue to exercise/ train outside! But that does not give license for folks to think they can excuse themselves from safety measures advocated by all informed health authorities, including mask-wearing, social distancing, and frequent hand washing.
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Re: Epidemiological question for Francois (or someone with similar professional chops) [Jae K] [ In reply to ]
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Jae K wrote:
Dr. Triax wrote:
Recently published, Maximal Exercise Capacity is Inversely Related to Hospitalization Secondary to Coronavirus Disease 2019, concludes that "These data further support the important relationship between cardiorespiratory fitness and health outcomes. Patients should be encouraged to regularly engage in aerobic exercise to maintain or improve their exercise capacity. Future studies are needed to determine if improving exercise capacity is associated with lower risk of complications due to viral infections, such as COVID-19".


There is so much scientific literature that show "heathy people are more likely to be healthy" and conversely "sick people are more likely to get sicker". ;-)
But really, since most observational research data suggest adverse outcomes are associated with obesity and certain co-morbidities, it serves everyone well to try to stay healthy though regular exercise.

And agree with everyone else here that outdoors is safer than indoors due to combination of greater dispersion of virus, ability to distance better, and quicker inactivation of virus by sunlight. And we should continue to exercise/ train outside! But that does not give license for folks to think they can excuse themselves from safety measures advocated by all informed health authorities, including mask-wearing, social distancing, and frequent hand washing.

my original question really wasn't intended to answer any of the following questions:

1. is being healthy a deterrent to contracting covid-19
2. is endurance fitness a deterrent to catching it?
3. does the act of racing suppress the immune system, rendering a race a bad public health paradigm?
4. can you catch the pathogen in the area where the race occurs, even if the race takes all appropriate steps?
5. is the act of traveling to/from an additional pathogen event?

all that stuff is good stuff, and i'm glad to get the answer, tho i think it's pretty clear what the answers are. but my question, in fact, had zero to do with fitness, or endurance fitness, or anything like that. my question had to do with ventilation. whether the act of ventilation helped to clear the lungs of pathogens. to be precise - whether there are other athletes in your vicinity or not - would an inhaled pathogen be more likely to be expelled during the course of increased ventilation associated with aerobic exercise?

i believe what your'e saying is no. it wouldn't. in fact, you'd be more likely to increase your exposure to covid-19. not necessarily your ability to fend off the bug once ingested or inhaled, because your immune system may be better prepared to fend off the bug because of the more robust immune system generated through aerobic fitness. however, as to the likelihood of scooping up and passing thru your epithelial tissue the pathogen itself, what i understand you to say is that i, out riding my bike, am at more risk of scooping up pathogens, like a basking shark scooping up plankton, than less risk of this. if i misunderstand, please disabuse me of my bad comprehension, and i thank you in advance.

Dan Empfield
aka Slowman
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