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Comment by Bartweiss | Hacker News Reader

The standout quote for me: "[immune cells] moved elsewhere, migrating to the animals’ guts or lungs, portions of the body that might be expected to need extra immune help after hard exercise".

Rapidly producing immune cells during exercise, then letting them (and more) die off would be a baffling response. But pumping them into the lungs (because you've been breathing hard through your mouth) and gut (for when you make up lost energy, and maybe eat some raw meat you've been hunting)? That makes a great deal of sense.

That effect is unconfirmed in humans, but it would ground our observations in an evolutionarily-sane outcome.

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Exercise pushes stuff around in your gut which is probably more directly related to the immune response than the possibility of eating raw meat.

Why would you go run (hunt) if there is still stuff (food) in your gut.

Best to hunt when you are loaded up on fuel. Don't want to be hunting when energy is low as you will most likely be less successful as your focus, patience, and response times will all be lower.

Hunting isn't like going to the store, success isn't guaranteed.

That is why you hunt when you are "out of fuel": you can try to hunt just after you eat, but when you fail you get to try again while "out of fuel". (Out of fuel in quotes - presumably the body has enough energy stores for a few more hunts even when it didn't find anything to eat the day before.)

My comment was definitely taken out of context, I didn't mean to eat and run out the door. The intent was you need to be well fueled and not depleted.

I think the opposite. People that fast for a period (> 16 hours) report improved energy levels. This may be because after a while the body enters a ketogenic state where it burns body fat, which is a great source of energy and perfect for when on the hunt.

Depending on food type it can easily take over 2 days to digest food. https://www.mayoclinic.org/digestive-system/expert-answers/f...

> I think the opposite. People that fast for a period (> 16 hours) report improved energy levels. This may be because after a while the body enters a ketogenic state where it burns body fat, which is a great source of energy and perfect for when on the hunt.

Ketogenesis requires over a week of carb restriction IIRC. I think fasting yields energy because the body increases various stress hormones to push you to find food so you don't starve.

No, it has to do with insulin levels. Google "Jason Fung insulin".

Have you ever tried fasting? One of the biggest issue while fasting is too much energy and difficulty to fall asleep.

Have you ever tried to focus on a hard problem at work after a big lunch?

It generally takes 40+ hours from the time you eat to the time you poo. So, humans always have stuff in their gut. https://www.mayoclinic.org/digestive-system/expert-answers/f...

Are fed hunters statistically more likely to successfully hunt than unfed hunters? It seems plausible, so hunters that took advantage of their fed state would have had an adaptive advantage.

As far as we know, humans' originally competitive advantage in hunting was long-distance running. Game could out-sprint humans but not out-distance human hunters. So, after successfully running down game, they must have had enough in the tank to complete the kill. This practice is still evident in some African tribes.

I've heard of persistence hunting, but I've never seen it suggested that was our primary competitive hunting advantage. Do you have a citation of some sort?

Also: "Statistically, their [marathon runners] odds of becoming sick were about the same as for anyone else in the race’s host city."

Yep - wasn't mentioned in the article, but I'd imagine the reason post-race marathoners are more likely to mistake coughs for colds is that marathons are also demanding. If your muscles ache and you're lethargic and coughing, that looks a lot like a cold.

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