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349 points zdw | 2 comments | | HN request time: 0s | source
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president_zippy ◴[] No.45652818[source]
Something about this just reminds me of when I did a literature review in my anatomy class to address the question: "Is running bad for your knees?"

I had to decide which of two sets of peer-reviewed publications that contradict each other was least guilty using the data to support the conclusion rather than letting the data speak for itself and making an honest conclusion.

Compared to PhDs, MDs hate designing an experiment and would rather just extrapolate a different conclusion from the same longitudinal study by cherry-picking a different set of variables. The only articles I bother reading from the NEJM anymore are case studies because they're the only publications that consist of mostly-original information.

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Root_Denied ◴[] No.45653259[source]
The fun part is realizing that any and all exercise comes with risks, and running probably is bad for your knees in the long term - but maybe the long term health benefits to the rest of your body of running outweigh the risk of damage to your knees.

Your personal health profile or family history may also put you at higher risk for cartilage degeneration from running, which would shift the balance in the other direction.

Blanket statements about medical outcomes like that are useful for medical practice in general, but can be misleading for individuals making health decisions if they ignore other relevant factors. There's also plenty of doctors who will not take those other relevant factors into account and just go by whatever the last training or research they were exposed to (which, incidentally, is also why big pharma companies invest in salespeople to target doctor offices - because it works).

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manwe150 ◴[] No.45660155[source]
Why “probably bad” though. If you plug that exact query into Google, numerous recent studies will tell you that it is probably good for long term knee health too (stress builds resilience unless prevented recovery time). Which studies are probably right?
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1. Root_Denied ◴[] No.45662356[source]
"Probably" is being used here because the body doesn't have a really good way to rebuild cartilage, especially as you age, due to lack of blood flow into places like the patella. Knee and hip replacements are on the rise (https://oip.com/the-lowdown-on-the-uprise-of-knee-and-hip-re...) as well in Boomers, indicating that age related degeneration (with or wihtout a history of running) is fairly universal and expected.

There's absolutely some perfect middle ground of "just enough" running that will strengthen, but not deteriorate too quickly, your knees - but again where that point is will vary by individual. It also may not be something that can be determined except in hindsight, partly because medical professionals generally don't start monitoring cartilage until the person is reporting pain or mobility issues (or a known condition they're checking for symptoms of).

Point being that statistically there are useful trends in aggregate data that can be observed, but, paradoxically, those trends don't necessarily translate to good general medical guidance. One counterexample where those trends do translate would be something like that peanut allergy study from 2015 that was linked on HN recently about introducing allergens earlier and frequently to babies, resulting in fewer teen/adult allergies.

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2. manwe150 ◴[] No.45663916[source]
> because the body doesn't have a really good way to rebuild cartilage

Okay, but I’m still noting that if you google this exact claim, numerous recent studies found that running is found to build cartilage, contrary to past assumptions