A formula for whether you should go back into a gym (or anywhere else)?

Posted on June 1, 2020

(Last Updated On: June 3, 2020)

This is the most helpful thought process I’ve come across for looking at what environments you should expose yourself to in 2020, and it’s rather simple:

“If a person’s occupational risk of becoming infected and risk of death from infection each approaches 10%, their occupational mortality risk becomes 1 in 100 — 10 times the annual occupational mortality risk among commercial fisherman, the highest-risk occupation in the United States.”


We have ourselves a little formula:

Risk of getting infected for a person * Risk of death if infected

= Risk of death per person

Per the article,

10% * 10% = 1%

For Risk of death if infected, we have some decent, albeit ever changing, data at this point:

“In a large case series in China, the case fatality rate was less than 0.5% among people under 50 years of age, 1.3% among those 50 to 59, and 3.6% among those 60 to 69. People with diabetes had a risk of death three times that of the overall cohort. These data suggest that the case fatality rate may approach 10% for people, like Ms. M., who are in their 60s and have diabetes — more than 20 times that among people under 50 without a high-risk chronic condition.”

The Risk of getting infected is a hard, if not impossible, metric to know. It will change, likely dramatically, based on social distancing factors, density of your environment(s), temperature and humidity?, etc. Frankly, we’re being generous by saying we’re guesstimating this number.

-> Individually, one way a person could possibly think about this is look at what percentage of their local area has been infected, and assume that’s their risk of getting infected, as it does seem to vary incredibly from say, county to county.

Of course, that assumes your daily dynamics are like the average person in your area, that doesn’t mean the current percentage will be the future percentage, we don’t know how many people are actually getting infected vs testing positive (some think for every one positive test, we have ten cases), etc.

But an example-

You’re under 50 years old, and we’ll say you have a 50/50 risk of getting COVID:

Case fatality rate for coronavirus if under 50 years old = 0.5%

Risk of getting infected * Risk of death if infected

= Risk of death per person

50% * 0.5%

= 0.25% risk of death per person

You could attempt to take this further -though you’re making a lot of assumptions here- by asking:

* How many people in that environment?

Let’s say it’s a gym that’ll hold membership / capacity to 100 people (and everyone is under 50 years old):

100 people * 0.25% risk of death per person

= 0.25 deaths

-> This is rather intuitive. The more people you allow to get together? The more deaths that can happen.

Now let’s say you’re over 50, with some risk factors, and “a lot” of the gym is also:

Your risk:

50% Risk of infection * 10% Risk of death if infected

= 5% risk of death

Gym risk:

50 gym members also above that age and have that risk profile * 5%

= 2.5 deaths

So, we have some different scenarios.

In one, people will think / feel / act like they’re doing something they do everyday: take a very low risk for some gain, like driving a car.

In another, many would consider it insane to step foot in, or reopen, a gym.

To one person, 0.25% will cause alarm as it would still qualify as the most dangerous occupation (by a lot). While someone else will say 0.25% is small no matter what it’s in relation to.

Then to another person, 2 or 3 deaths may be inconsequential, yet to others, having 2 or 3 of their gym members die could be haunting, if not be grounds for out of business.

-> To be clear, I’m not saying the business was necessarily at fault here. I’m saying the perception of “what is happening at that gym?” could easily be enough to topple a business.

Feel free to get more granular, such as assessing your risk if you’re under 35 with or without risk factors (namely: diabetic, obese, hypertensive). Or find non-China data if that’s a big deal to you.

Keep in mind it is always prudent to give yourself a margin of safety. For example, you’re 35, but use the 40-50 year old data. Or you’re 25, but double the case fatality rate just in case you have a risk factor we don’t yet know about or not accounted for above. (Your race / economic / health insurance situations being big ones off the top of my head.)

Preempting poor probability thinking 

I suspect this article or line of thinking will cause some to double down on the whole we shouldn’t have done one size fits all, lockdowns were stupid, it’s all a sham, OPEN MY DAMN GYM NOW!!!, etc.

That’s a sorry, lazy ass way to think about risk. We now have the benefit of hindsight, where we can quantify the risk based on demographics to a reasonable (not perfect) extent. When you have no idea what the risk is, biological instinct tends to default to maximum safety. When a deer hears an unusual sound in the woods, it runs. Better to be too cautious when not being cautious enough means getting killed.

So, just because maximum safety for all might not make sense now does not mean it made no sense then.

-> Please remember I’m no epidemiologist. The only reason I’m doing this is because the guidelines being given for whether it’s safe “out there” have been terribly confusing and inadequate, leaving us all to figure this out for ourselves. This is my best effort, so far. I by no means know it to be the best effort.

I bring this up because, as I’ve gone over, one thing we do not know is the risk of exercising around dramatically increased disinfectant use. I don’t know how you can currently quantify that, beyond complete guessing. (Not estimating, not guesstimating, but pure guessing.)

In a year or two, we’ll find there were plenty of people who went back into a gym and are fine. (But it might take a decade or two to know whether you really did any harm or not.) Causing many to say worrying about it was idiotic. Others will hear of someone who got sick from doing so and chant how irresponsible it was.

Without context, that level of general bemoaning is both sides being clueless. You do not judge a probabilistic decision by its outcome. You judge it by the information you had when you were forced to make the decision. 

We’re now also getting to where we have to judge decisions by the risk(s) people said they were ok taking. We don’t call an extreme athlete who gets injured an idiot. We call them an idiot if they claim they thought they’d never get hurt. That’s very different.

So, speaking of athletes, if an athlete is willing to go back in a gym because the risks of getting sick are outweighed (to them) by the chance to make millions of dollars, because they feel their gym, for one reason or another, is that necessary, then alright. But a person with all the same traits except for the ability to make millions might easily justify exercising outside instead.

For one person, a little less performance can be life changing, whereas for another it’s trivial.

We now have some better information. We can now make better decisions. We can even get somewhat formulaic, but we’ll never be able to get all the way there. We’ll never be able to exactly quantify the risk of death against the benefits of going back into a gym. We’ll still have to use some of those biological instincts. Where anybody speaking in absolutes now is still as mentally deficient in probability as those who did months ago. 

Because this is the point of probability: we’re not dealing with 100% or 0% odds here. Consequently, we can’t bet, or judge, in those terms either.

One ancillary, yet big, reason why? Note there has been zero mention of longterm negative effects of getting the virus. All we’ve done above is look at the risk of death. This is getting beyond the point of this post, but you don’t have to look far for health professionals who have serious concerns about COVID patients who survive, yet had blood clots, reduced lung capacity, etc. possibly causing irreparable damage.

Our ability to project risk here has gotten better, but we’re still playing a version of Russian roulette. We know we have more than 6 chambers in the gun (meaning our risk of death is better with coronavirus than Russian roulette), but there’s still a lot we don’t know.

It’s understandable some people have decided to sit down at the table. It’s also fair some still haven’t.

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