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Comment by kristiandupont | Hacker News Reader

That ice would reduce swelling feels intuitive to me. What is less intuitive is whether or not reducing swelling is in fact a good thing.

The way I see it, swelling could be one of two things:

1) a mechanism that the body engages in order to heal or alleviate healing, similar to fevers, or

2) a negative side-effect caused by, say, inflammation or something.

There are probably studies that indicate which of the two it is, I don't know. But if it is #1, then reducing it is just a way to actively work against the body.

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It's always been curious to me that a number of things we do some to be counter to our own bodies' healing mechanisms.

Besides trying to reduce inflammation, the other big one of course is antipyretics, or fever reducers. Fever is a big trigger for our bodies' innate immune system, both helping to denature bacterial and viral enzymes and triggering the recruitment of defense cells. Suppressing the fever unnecessarily (i.e. when the fever itself isn't causing harm) seems to have a significant effect on the body's ability to fight pathogens.

> "the use of antipyretic drugs to diminish fever correlates with a 5% increase in mortality in human populations infected with influenza virus and negatively affects patient outcomes in the intensive care unit."

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4786079/

An explanation that I was given (note: by a pharmacist, not a doctor or sports therapist) was that swelling is your body's way of "splinting" the injury so that you can keep moving in a survival situation. However, it delays/inhibits healing.

While survival now at the expense of long term healing was probably a good tradeoff for our ancestors living in the wild, it likely no longer makes sense for modern people outside of emergency situations.

I want to emphasize, that this was just an explanation that I was told. No actual evidence was given.

I've never heard the "splinting" explanation before. I've been told that it's the body's way of prioritizing the routing of plasma and red/white blood cells to the damaged area for cell repair and immune response as well as clearing out damaged tissue. I've also been told that the only bad inflammation is chronic inflammation.

This was from a sports medicine doctor during a conversation about our sports trainers. The doctor was also against the heavy use of cryotherapy by our trainers because, according to her, it prolonged recovery. She actually encouraged applying heat instead of cold for non-injuries (e.g., post-workout, pre-competition, etc.) where your body may not have an inflammatory response to increase blood flow to the areas and that applying cold would just increase the chance of actual injury.

That is a fine example of a third explanation which seems equally plausible to me.

Of course, the topic is very similar to all the conversations about ChatGPT: are eyebrows "made" to protect the eyes from dripping sweat? No, because evolution has no intention. But it sure was convenient.

Acute inflammation is there for a reason; it helps repair tissue damage. At the cost of function in the short-term. My bet is that icing means you can use your wrist again sooner, but with prolonged or incomplete recovery.

> Acute inflammation is there for a reason; it helps repair tissue damage.

Inflammation is primarily to address severe trauma, like having a limb severed or torn apart. That doesn't necessarily mean it's good for all tissue damage, but evolution often can't make such fine distinctions, so our body triggers inflammatory responses even when it's counterproductive. The inconvenience a counterproductive response is much better than the death that follows from not having any response.

A lot of medicine is about controlling the body's inappropriate inflammatory responses. We don't always have a good handle yet on when the body's inflammatory response is good vs. bad in all cases, which is why the debate over icing is ongoing, but it is clear that it often isn't beneficial. I think it's also clear that icing and NSAIDS for chronic inflammation are not good ideas.

source?

> but evolution often can't make such fine distinctions, so our body triggers inflammatory responses even when it's counterproductive

This is just not accurate, and I'd love to see your source on even the first clause here. because evolution does, in fact, make fine distinctions all over the tree of life.

To be clear, given what you quoted, your claim is that inflammation is almost never wrong?

My claim didn't really have to do anything with inflation specifically, just that evolution itself can make fine distinctions.

It looked like you were calling the whole sentiment wrong, not just the first half (and ignoring the word often). Okay then.

I imagine the claim was more that evolution gives systems that at the individual level aren't that fussy about the details, not that evolution can't produce highly specialised organisms.

Or in other words, ducks imprinting on a dog is a thing: https://www.youtube.com/watch?v=6qidueuojrc

> because evolution does, in fact, make fine distinctions all over the tree of life.

I said evolution often can't make fine distinctions, not that it never can. The inconvenience of improper inflammation was clearly never so great that it impacted reproductive fitness, where death resulting from no inflammation clearly does.

Another factor when it comes to evolution is that it doesn't care much what happens to us when we get old. If it can trade increased fitness during our reproductive primes for a lot of aches and pains in our 40s, it will happily accept. You don't hear too many 16-25 year olds complaining about inflammation.

> Inflammation is primarily to address severe trauma, like having a limb severed or torn apart.

Source?

How would an actual scientist even prove or disprove this statement?

But the body during evolution didn't have access to ice (studying polar bears and pinguins might be interesting).

So it could be that ice is a good thing, just like air conditioning is a good thing, but nature had no way of evolving that.

Well ice is there to UNDO some of our body's responses, so it does not do something the body could not theoretically achieve.

Overdoing it with one mechanism then compensating for that with some other mechanism is so like biology though. Biology is like a junior programmer who is rushing to meet a deadline. If it can slap a bandaid on somewhere instead of refactoring, it will nearly always do that.

Swelling means that your body is directing more blood than usual to this location. More nutrients, more antibodies, etc.

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