This Podcast Will Kill You - Ep 138 Fever: Take it to the limit

Episode Date: April 30, 2024

A dull pounding headache. Body aches that come and go. Chills that set your teeth to chattering and have you reaching for the fluffiest blankets to warm up. But the thing is, you’re already warm, hot even. At least according to the thermometer. That’s right, you’ve got a fever. Throughout the years of making this podcast, we’ve begun many a disease description with “it started with a fever” but we haven’t ever explored what that really means in depth until this episode. We take you through why fevers happen, how they work, why on earth you feel cold when you’re actually running a temperature, and whether they’re helpful, harmful, or somewhere in between. We then poke around in the history of thermometers, exploring when someone first thought to measure human body temperature and how that changed the concept of Fever the disease to fever the symptom. This is a red-hot fever dream of an episode with some very fun fever facts, so make sure to tune in! See omnystudio.com/listener for privacy information.

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Terms and conditions apply. Visit blueapron.com slash terms for more information. I'm Amanda Knox, and in the new podcast, Doubt, the case of Lucy Letby, we unpack the story of an unimaginable tragedy that gripped the UK in 2023. But what if we didn't get the whole story? Evidence has been made to fit. The moment you look at the whole picture, the case collapsed. What if the truth was disguised by a story we chose to book?

Oh, my God, I think she might be innocent. Listen to Doubt, the case of Lucy Letby, on the IHeartRadio app, Apple Podcasts, or wherever you get your podcasts. This is Special Agent Regal, Special Agent Bradley Hall. In 2018, the FBI took down a ring of spies working for China's Ministry of State Security, one of the most mysterious intelligence agencies in the world. The Sixth Bureau podcast is a story of the inner workings of the MSS and how one man's ambition and mistakes opened its fault of secrets. Listen to the sixth bureau on the Iheart radio app, Apple podcasts, or wherever you get your podcasts. Experiment 1. A large vessel containing 170 gallons of saltwater

was placed in the open air. The atmosphere was damp and raw. The thermometer, both in the air and in the water, stood at 44 degrees Fahrenheit. The subject of the experiment, was Richard Edwards, a healthy man, 28 years of age, with black hair and a ruddy complexion. The hour chosen for his immersion was four in the afternoon, about two hours after his dinner. A time, Dr. Curry tells us, appointed rather for his own convenience than as being most proper for the purpose. The heat of the person who was the subject of the experiment was 98 degrees before undressing, his pulse 100 in the minute. He was undress. He was undressed. He was undressed. dressed in a room where the mercury was at 56 degrees and afterwards stood naked before the fire

till his heat and pulse were examined again and found as before. He then walked pretty briskly into an open court where the northeast wind blew sharply upon him. He was exposed to it for a minute and then plunged suddenly into the water up to the shoulders. The thermometer, which had been kept in a jug of warm water at the heat of 100 degrees, was introduced into his mouth, with the bulb under his tongue, as soon as the convulsive sobbinges occasioned by the shock were over. The mercury fell rapidly, and a minute and a half after immersion, it stood at 87 degrees. He remained motionless in the water, and the mercury rose gradually. At the end of 12 minutes, it stood at 93 and a half degrees.

Dr. Curry expected to see the mercury rise on changing the medium of water for air, and therefore he kept him exposed, naked, to the wind, two minutes after taking him out of the bath. To his surprise, although the attendants were rubbing him dry with towels during this time, the mercury fell rapidly. He was put into a warm bed, and his heat, when examined under the tongue, was 87 degrees. Frictions were used and brandy mixed with water administer. three hours afterwards, however, he had not entirely recovered his former heat. But by eight at night, he was in all respects as usual.

Convulsive sobbing. As soon as I read that, I was like, that's the one. Oh. Yeah. They kept him cold for so long. So keep in mind, that was experiment. one. Experiment one? In subsequent experiments, Dr. Curry seemed only encouraged to try harder. Okay. So like the experiment seven, which I almost included, and I was like, no, no, that's enough.

I'll just read you a little bit. It's supposed to be tried on Richard Sutton, age 19, of a pale complexion and feebler frame. Okay. And then it said, so he was in the water, intended to be tried. to be in the water for 45 minutes, but only made it to like 35. And then when they put the thermometer in, the doctor was like, well, it's reading 83 degrees, but it must be that his teeth are chattering so much. And so it's just the cold air causing the temperature drop. Oh, God. So that was from an experiment, I don't know, a paper by James Curry. titled An Account of the Remarkable Effects of a Shipwreck on the Mariner's, with experiments and observations on the influence of immersion in fresh and saltwater, hot and cold, on the powers

of the living body from the same work from 1794, which explains like the most long, detailed title and also like... The title that tells you everything they did in the paper. Yeah. Oh, wow. Well, that's a lot. Yeah. Hi, I'm Aaron Welsh. I'm Aaron Olman Updike. And this is, this podcast will kill you. I like forgot that I had to do that part. Well, I mean, we did half the episode, it seems. It really does seem like that. Yeah. It was a long one.

Oh, but really good. Really, really sets us up well, I think, for today's topic, which I am thrilled about. Mm-hmm. We are veering just slightly off course of, of typical. really not that far off course, let's be honest. Yeah. We are talking today about a medical invention called the thermometer. The thermometer. The thermometer. So I will say this is my little kind of caveat is that the focus.

I would say about half of my part is on the thermometer. Okay. Yeah. I'll explain later. Okay, I can't wait. I'm going to talk about fevers because, like, what do we use a thermometer for? Checking if you have a fever. That's mostly what I'm going to be talking about, too. Great.

It'll be good. I can't wait. It's going to be really fun. Yeah, but we have a few things to get out of the way before we get into, like, the content. Of course we do. Yeah, it's quarantini time. It is. And we're drinking this week, give me fever. Give me fever. Like the song. Give me fever. Wow. That's the song, right?

That's the song, yeah. In Give Me Fever, we figured we would have to do like some sort of hot cocktail. Something spicy. Hot, yeah, hot isn't spicy. And so we're doing, and I don't know if we've done this before, but we're doing a pineapple margarita. With jalapeno. And mescal. Don't know if we've done this exact variation.

Hope not. But it's delicious. and we will post the full recipe for the quarantini and the non-alcoholic placebo rita. On our website, this podcast will kill you.com, as well as on all of our social media channels. We sure will. Yes. On our website, this podcast will kill you.com, there's just so many things that you can find there. You can find transcripts from all of our episodes.

You can find sources that we use for every episode. You can find our bookshop.org affiliate account and our goodreads list and our merch and our Patreon and Bloodmobile, who does our music and of contact us form and of firsthand accounts form. It just keeps going on and on. It's the website that keeps on giving. So check it out. And what else? Business.

If you haven't already, please rate review and subscribe. It helps us so that other people can listen to this podcast as well. Yeah. Send us episode suggestions, you know? Yeah. Weekly episodes, we need some ideas. You have lots of them. And thank you to everyone who has sent incredible suggestions.

We are taking you up on some of those this season. It's going to be a great season. Well, should we get into fever? Yeah, I think we should. Let's take a quick break and then jump in. Dinner shows up every night, whether you're prepared for it or not. And with Blue Apron, you won't need to panic order takeout again. Blue Apron meals are designed by chefs and arrive with pre-portioned ingredients.

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Order now at blue apron.com. Get 50% off your first two orders plus free shipping with code this podcast 50. Terms and conditions apply. Visit blue apron.com slash terms for more information. Anyone who works long hours knows the routine. Wash, sanitize, repeat. By the end of the day, your hands feel like they've been through something. That's why O'Keeffe's working hands hand cream is such a relief.

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is outside. We're offering our listeners 15% off their first order of O'Keef's. Just visit o'Keef's company.com slash this podcast and code this podcast at checkout. China's Ministry of State Security is one of the most mysterious and powerful spy agencies in the world. But in 2017, the FBI got inside. This is Special Agent Regal, Special Agent Bradley Hall. This MSS officer has no idea the U.S. government is on to him. But the FBI has his chats, texts, emails, even his personal diary. Hear how they got it on the Sixth Bureau podcast. I now have several terabytes of an MSS officer, no doubt, no question, of his life. And that's the unicorn.

no one had ever seen anything like that. It was unbelievable. This is a story of the inner workings of the MSS and how one man's ambition and mistakes opened its fault of secrets. Listen to the Sixth Bureau on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. I'm going to try and start at the beginning here.

Ready? Pretty much all animals seek to exist at a particular temperature set point. We have to do that. And this particular temperature that our body likes to exist at varies animal to animal. I'm not going to get into the details of it. Endotherms, like mammals, like us, maintain our temperature by physiologic mechanisms, like energy production and then vasodilation or sweating to cool ourselves off if we get too hot

and produce too much heat, or vasoconstriction, or shivering, or non-shivering thermogenesis if we get too cold. As endotherms, we generate our own heat via our metabolism in our body, and our brain, specifically our hypothalamus, has an internal thermometer that keeps really tight control over our temperature. Humans have to stay at around 37 degrees Celsius, or netheralm. 98.6 Fahrenheit plus or minus like one degree. And our body and our brain does a really, really good job of keeping us there, despite the fact that as humans, we live at all of these extremes of temperature. And despite the fact that we have massive fluctuations in our energy expenditure and our energy intake and all of these things. Why? I know. I know. I'm not, I'm interrupting

you. Why 98.6 or thereabouts? I have no idea. That's a really fun and interesting question because it totally varies mammal to mammal. I mean, dogs and cats run a lot warmer. Birds are super warm. And then you have things like opossums, which are like 94 degrees. Right. Well, and bears. Oh, I did a little bit of a deep dive on bears. And like animals who hibernate in the winter. Yes. God, we love some hibernation. I know. But I don't know. I don't know why each animal has evolved their particular temperature. I assume it has something to do with the rate of metabolism.

Right. So there's like body size in terms of metabolism and stuff like that and like heart rate. But it could also just be like drift to a certain extent. Like there might not be like a driver of it. Exactly. Oh, I have a lot of feelings about drivers in general. We'll keep talking about like evolution of certain things. I'll let you keep going. Okay, it's a great question, though. So extremes of temperature can and do, as we heard in our first-hand account, result in things like hypothermia.

86 degrees is not okay for a human body to exist at. Or heat stroke on the other end, which kills lots of people every year. But here's where things get really interesting. In hypothermia or in hyperthermia, so when we are exposed to extreme, streams of environmental temperatures, our brain would still be doing its darned us to keep our bodies at a balmy 37 Celsius. Our temperature set point would remain the same. A fever is what happens when our temperature set point gets moved. When our body, our brain, our hypothalamus that's controlling our temperature set point decides, and we'll talk about why and how, decides, we got to heat things

up a little bit. And so it moves that temperature set point. And then our body actively seeks to raise its temperature. And that's a fever. Okay, when can I start asking more questions? Should I just let you keep going and assume that you'll explain it all? I mean, I'll probably answer them, but like, I guess what order you want things in, you can hit. at me with questions now. No, no, no, just go, just go. Okay, okay. Because if I don't answer them, then it'll be really fun to try and figure out how to answer them. The first question that I assumed that you would ask is how high is a fever? But maybe that's too easy of a question. But it turns out actually when I was reading this, that like different places actually do define

it differently. So it made me feel like I need to get off of my high horse a little bit. Um, because I do exist on a high horse when it comes to fever? Wait, wait, what do you mean by how you exist on a high horse when it comes to fever? Well, okay, I have always 100% of the time learned that a fever is anything above 38 Celsius, which is 100.4 Fahrenheit. So like, there are a lot of times when people will say, oh, I had a small fever like 99.9. That is not a fever. That is my high horse.

That's me on my high horse. You correcting someone? Thank God they didn't also say a spider is a bug. They would be dead to you. It would be the end of a friendship for sure. Anyways. Yeah. So is there a difference between low-grade fever?

Okay, is this where you're going. I'm so glad that you asked that question. I hate the term low-grade fever. I guess we're not friends. But that's just me. Like lots of people use that term. So when I then was digging into this, some organizations like the Infectious Disease Society of America and the American College of, oh, I forget the actual acronym, but it's the

intensive care like academy in the U.S., they actually said that they kind of consider it more like 38.3 Celsius or 101 Fahrenheit, which is even higher. Wow. So you could have been even higher on your horse. Exactly. It could have. Like, 999 is definitely not a fever. But it's really, if you think about it, if you think of 37 as the kind of human typical temperature set point, it's plus or minus one degree is normal.

And our temperature is going to vary throughout the day. So one degree off is really not. that abnormal. And so I think that that's kind of like the main point is that, and we'll really get into like what happens when we have a fever and like, is it bad? Is it good? What, what? What? And so I think that's why in a kind of critical care scenario, you might end up tolerating a little bit higher before you need to say this is a fever that we need to do something about, if that makes sense. Okay. And when it comes to a fever, our body also generally has a lot of mechanisms in place that keep this from getting too high. Usually it stops around 41 Celsius or

105.8 Fahrenheit, although some papers that I read said that pre-antibiotics, we saw more like 42 degrees Celsius or 107.6. So it's not that it's impossible to go higher. But usually if it's a fever and not heat stroke or heat exhaustion that's happening from external factors entirely, but a fever caused by this shift in your internal set point, then there's also these mechanisms in place that will stop it from getting too high. So then what is causing this? Like why does our brain decide all of a sudden to change our temperature set point and thereby cause a fever? Most of the time, it takes two different things to start a fever. It takes some exogenous substance, something from outside of us that we do not produce, like for example, a bacteria,

endotoxin or like viral proteins, something that our body recognizes as foreign, as not self, that interacts with our immune system. And then it takes substances that we do produce. And these are called pyrogens. Really, they're both called pyrogens, exogenous and endogenous pyrogens. Our endogenous ones are things like interleukins and TNF alpha, and I'm not going to get into the nitty-gritty because it's not that important. The point is that these things together act on our hypothalamus where that temperature set point is. And our hypothalamus then produces something that we've talked about on this podcast before, which is prostaglandin E2, which acts on yet another part of our hypothalamus, to kind of

slow down how much our warm, sensitive neurons fire. And that's what then results in the increase in our body temperature. Now, the deep, deep details of like what's hitting what and why is it doing X, Y, Z, we don't fully understand, but that is the basic picture of it. It's stuff in our body that our immune system recognizes, usually bacteria or viral infections, that then trigger our brain to say, hey, we need to raise the temperature. So that really raises this question of, a fever, this adaptive mechanism to fight off infections? Because the vast majority of the time, or maybe not the vast majority, but like a lot of the time, a fever is associated with an infection.

So there is a lot of literature about this hypothesis that because fever is this response to infection, that it has adaptive significance specific to reducing pathogen survival. And we talked about this kind of in our blastomycosis episode, just in like, yeah, how the evolution of endothermy and like having a higher body temperature at baseline might have been adaptive against fungal pathogens like blastomikosis. So then if you take that one step further

than perhaps having a fever, intermittently raising our temperature even higher, protects us against other pathogens as well. And we do have some support for this idea, both directly and indirectly. So indirectly, there's a lot of evidence that ectotherms, like lizards, will lay out in the sun to induce a fever. They will raise their own body temperature in order to fight off pathogens when they're infected. Or fish, some fish will swim to warmer water if they're infected, which I find so cool.

Really cool. Now, in humans, the studies are a little bit maybe more indirect, I guess. I don't know. But in some studies, for example, in the ICU, people who have sepsis and have a fever that's not too high, so usually not above like 41 or 40 even Celsius, people who have a fever have lower mortality rates than people who do not have a fever. But if that fever gets too high, then it's no longer true. And then there is also like in vitro studies that show that various organisms that tend to cause infections in humans do poorly at higher temperatures. And that fever, one like hypothesis as to the mechanism of why is that increased temperatures increase the iron requirements of bacteria and then reduces their survival. I also found this really fun paper that tried to like dig deep onto like different hyper.

to like different hypotheses of like how you can inhibit pathogen growth. It's too much detail, but I'll post it because it's really fun. But the idea is just that we have pathogens that are less well adapted to survive at higher temperatures. So raising our body temperature helps us to fight off those infections. I mean, that's the idea. And also the fact that fever is highly conserved across mammals. Like mammals in general have fevers.

So like, and whether it's adaptive across the board, I don't think, I actually I don't think anyone has, has really like tried to argue that point specifically. Like I think it's always been there's nuance to it because back even in the 1920s or even before then, people were seeing fever as being adaptive, but also realizing that some pathogens cause fever on their own and actually replicate better. i.e. malaria, parasites, replicate better at higher temperatures. So it depends, I guess. It depends, Aaron. And fever is not a response that's specific to pathogens, either. So we also can see fever in malignancies. We see fever in autoimmune conditions. Now, in those cases, it's very likely that the fever mechanism, like the generation of that fever, is due to the same underlying inflammatory mechanisms, right? It's still like our immune system activating the same pathways just without the presence of a bacterial endotoxin to start it off, if that makes

sense. But then we also see fever in people with traumatic brain injury. We see fever from endocrine disruptions like hyperthyroidism. And then there's also like drug-induced hypothermia where you can get incredibly high body temperatures as a result of drug interactions, which is kind of separate, like a separate mechanism entirely. So then the question is like can fever be bad? And like the short answer is yes, definitely. Yeah. And part of it is that fever is not an isolated phenomenon. I have, yeah. So your face just like.

I have a question. I have a question. Okay. Are there people who do not get fevers or cannot change that set point? That's an excellent question. Definitely. And I think that's part of why, so in some of those studies where they have looked at patients in ICU's who have sepsis, people who don't have a fever at all, who are.

either normothermic or even hypothermic have less good outcomes, like higher mortality and things like that. So not being able to mount a fever response is usually a sign that your immune system is not activating enough. So in terms of what the specific cause of that could be, I don't have like a list of things for you, but definitely there are instances where you could have an immune system that's not able to mount a febrile response. But I mean like just people. like that is you you can never not just situationally but like can have never been able to have a fever I don't I don't know if there's like a documented human who's never fevered well I'm just it makes me think a lot about like why is it in this part of the brain

hypothalamus when did we talk about prostate glandins on this oh when we talked about Tylenol and when we talked about oh yeah that makes sense yeah aspirin yeah yeah Okay. Yeah. Anyway, interesting. I'm like, I, I, now I'm sort of even struggling to think about like body heat, period. Oh my gosh. What is it? I have deep. I've got like four more pages from a paper that goes deep into like the generation of heat, uh, in mammals and different mammals and like heat generation and heat loss and all of these like thermodynamics stuff. Because there's a lot there. I can't wrap my head around it, so sorry to have interrupted. Let's just keep going. It's okay. That's okay. It is really fascinating.

Anyone who works long hours knows the routine. Wash, sanitize, repeat. By the end of the day, your hands feel like they've been through something. That's why O'Keeffe's working hands hand cream is such a relief. It's a concentrated hand cream that is specifically designed to relieve extremely dry, cracked hands caused by constant hand washing and harsh conditions. Working hands creates a protective layer on the skin that locks in moisture. It's non-greasy, unscented, and absorbs quickly.

A little goes a long way. Moisturization that lasts up to 48 hours. It's made for people whose hands take a beating at work, from health care and food service to salon, lab, and caregiving environments. It's been relied on for decades by people who wash their hands constantly or work in harsh conditions because it actually works. O'Keefs is my hand cream of choice in these dry Colorado winters. when it feels like my skin is always on the verge of cracking.

It keeps them soft and smooth, no matter how harsh it is outside. We're offering our listeners 15% off their first order of O'Keefs. Just visit O'Keef's company.com slash this podcast and code this podcast at checkout. In 2023, a story gripped the UK, evoking horror and disbelief. The nurse who should have been in charge of caring for tiny babies is now the most prolific childcare. in modern British history. Everyone thought they knew how it ended. A verdict?

A villain. A nurse named Lucy Letby. Lucy Letby has been found guilty. But what if we didn't get the whole story? The moment you look at the whole picture, the case collapses. I'm Amanda Knox, and in the new podcast, doubt the case of Lucy Lettby, we follow the evidence and hear from the people that lived in. To ask what really happened when the world decided who Lucy Lettby was.

no voicing of any skepticism or doubt. It'll cause so much harm at every single level of the British establishment of this is wrong. Listen to Doubt, the case of Lucy Letby on the IHeartRadio app, Apple Podcasts, or wherever you get your podcasts. China's Ministry of State Security is one of the most mysterious and powerful spy agencies in the world. But in 2017, the FBI got inside. This is Special Agent Regal, Special Agent Regal. Special Agent Bradley Hall. This MSS officer has no idea the U.S. government is on to him.

But the FBI has his chats, texts, emails, even his personal diary. Hear how they got it on the Sixth Bureau podcast. I now have several terabytes of an MSS officer, no doubt, no question, of his life. And that's a unicorn. No one had ever seen anything like that. It was unbelievable. This is a story of the inner workings of the MSS and how one man's ambition and mistakes opened its fault of secrets. Listen to the Sixth Bureau on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts.

But when we look at fever specifically, it's not an isolated phenomenon. Your brain is not causing a fever and that's the only thing that's happening in your body, whether it's during an infection or during malignancy or whatever the cause is. The mechanisms of that inflammatory response that are triggering fever also trigger things like an increase in your heart rate, an increase in your metabolism, and oxygen requirements. And these things are not physiologically benign, right? They are costly for us. So that is one way that fever can actually cause more damage, right?

it's metabolically very costly to have a fever because of all of the other things that come along with it. But on top of that, at a certain point, the heat alone damages ourselves. So we see both cellular and tissue level and then even like organ level damage as a result of that increase in body temperature as a result of fever. And so it makes sense then that there are usually these mechanisms, in place, these kind of negative feedback loops that kick in over certain temperatures in order to keep our fevers from getting too high. But you're right, there are situations in which those fail. And there's a few ways to think about that, depending on what the cause of fever was. If it is something like sepsis or an overwhelming infection, then a fever that is getting so

incredibly high that it's causing things like brain damage or other organ damage is a sign that the damage has already begun. And so your body can no longer regulate that fever cycle, if that makes sense. And the same thing is true if it's a cause like a TBI, like a traumatic brain injury, where you've just, you've disrupted the ability to do that temperature regulation, period. Why when you have a fever do you feel cold? Oh, that's a really good. That's a really good question. From what I read, it's because your body is trying to raise its temperature. And so it's doing that by things like vasoconstriction in your extremities in order to funnel the heat into your core. So you're going to feel cold. It's also then behaviorally going to cause you to

put on layers, which is going to help you raise your body temperature. How cool is that? Huh? Yeah. Yeah. So it's not, I think what's interesting too is a lot of times people are like, oh, if you have a fever, you should try and cool your body down. You should put on cold, you know, put a cold cloth on, et cetera. But that is going to fight against what your body is trying to do. So then it will actually probably cause you to shiver more, which is the way that you're trying to generate heat. Shivering is trying to generate heat. So it kind of like works against yourself to do those mechanisms. It doesn't mean they're harmful necessarily, but it's interesting. But then also like, okay, maybe this is.

is just I'm thinking of, I don't know, the secret garden or something. Okay. Yeah. But isn't like ice bath when the fever is out of control really high where you can sort of like overwhelm externally your body to the point where it brings the temperature down. It sounds and it looked from the movie, Secret Garden, really painful. Yeah. I don't know that in a fever situation, an ice bath would be the way to lower.

your temperature. In a hyperthermia like situation, something like that, yes, potentially. Okay. Right? Like it, like because your body got overheated externally. Like heat stroke type of thing? Exactly. Heat stroke type of thing. But this was not that, but no. I think, I think we have better ways than an ice bath to lower body temperature. It was like the early 19. Right. They didn't in the secret guard. garden. We do today. Okay. Good to know. Yeah. Don't do an ice bath. Not that I'm telling you what to do. This is not medical advice. But yeah, that is kind of, that that is the, the fever. That's the fevers. That's it. That's what I have. Did you have more questions? I have a lot more things I could talk about, but that was what I really wanted to get across. Yeah. Okay. So talk to me.

about the, when fevers get out of control, why does it cause certain types of responses? Like convulsions, seizures? Like seizures? Okay. Seizures, we don't, febrile seizures, we don't fully understand, like straight up. Febrile seizures are most common in young kids. They're not impossible to happen in older individuals as well and in adults. But they're most common in young kids.

and you don't have to have a high fever to have a feveral seizure. Like it's not necessarily a function of how high the temperature is. And it's not indicative of damage, really. What we think is going on is that the same cytokines that are inducing fever also can result in increases in excitatory neurotransmitters and decreases in the inhibitory neurotransmitters. So increases in glutamine decreases in GABA. And so that, those things together can result in seizures, right? Okay. So it's not necessarily a result of the temperature.

It's a result of the other parts of the inflammatory response that are doing the same thing. Why is it more common in kids? I don't fully know. But is it because, like, their brains and neurotransmitters are just not all online the way that adults are? Okay. Probably that. Question about treatments. Like, so obviously, you know, we've covered a couple on the podcast before.

Yeah. Aspirin acetaminophen slash paracetamol. We have to do ibuprofen. We do. Someday. Someday. And probably something else. Am I forgetting something?

Those are really all that I know about. Which is kind of interesting. I guess quinoin, which we've already talked about. But this kind of goes along with the whole like, evolutionary medicine type of thing, which I like very briefly touch on in my section in terms of just like mentioning that there is this conversation sometimes that that springs up about when to treat a fever. And are we being, are we fighting against our millions of years of evolution leading to this response that is in many ways good for us or protective?

Potentially. Yeah. Potentially. So like, yeah, is there sort of, are there guidelines for this or is this not really, I don't know, yeah. It's such a good question. There's not guidelines for it, at least not for like normal people living their normal lives. There are, you know, guidelines for like ICU's where there's, you know, consensus of this is when you should investigate versus treat a new fever in the ICU type setting because that's, you know, where we have like the most data. But really, there's not a ton of clinical evidence one way or the other to say like, oh, we should be treating fevers because the fevers are detrimental on their own.

Or there's not data saying like we should let fevers run their course because treating a fever causes more problems than letting it run its course. We don't have the data to say that one way or the other. And I feel like, I mean, I guess you could probably design studies that would be not be entirely unethical to do this. You know what I mean? Yeah, you could. I think that part of the problem is just that it's so, the medicines that we use,

like acetaminophen and ibuprofen are just so common and so generally safe and well-tolerated. Right. And fever suck, man. They do. They feel crappy. And so I think that that is why they're just so. common to be used. But I do think that what, what to know that a fever has even the potential to help, like is a sign that our body's immune system is doing what it is supposed to do and is

trying to fight off this infection. If it is a result from an infection, right? Like assuming that it's, you have a fever because you have an infection. What I think that can provide is just like a piece of mind that like there is no data saying we have to treat a fever if if you are not uncomfortable from it or if you're sleeping through it or like whatever the situation is you don't have to treat it right and I think that that like we don't have data that says you have to treat a fever in order to prevent harm even if it gets pretty high quite honestly. Is this is my moment to tell you about my high fever that went untreated? Yes. Okay. So I was I was a freshman at the University of Kentucky in 2005.

And it was my first semester. I was living in Donovan Hall with my roommate, Megan. And it was like really just pretty early on. And I got sick, you know, like achy. I don't even know, sore throat probably. And I don't remember much of the week. And I missed class a few days in a row. And I was the first time living on my like,

living on my own, quote unquote. And I just laid on my top bunk for days, covered in blankets, freezing, couldn't even watch Gilmore Girls, which I watched religiously at the time. I do, I remember like vaguely seeing like the intro and then just passing back out. And then on, I feel like it was Thursday or Friday, my, in the afternoon, my roommate came back from class and she was like, I am really worried about you. This is bad. Like you have not moved. Have you eaten anything?

Have you had anything to drink? And I was just like, could not take care of myself because I was used to my mom taking care of me. And we didn't have a thermometer. We didn't have any sort of Tylenol, ibuprofen, anything to like relieve fevers. Yeah. Of course not. So then I walked like the half a block with my roommate. My roommate was like, we're going to campus health right now.

And I remember almost passing out on the walk. Oh, my God. And I get in, this is such a longer story than I intended it to be. Get into the doctor's office. They see me right away. And the doctor, she takes my temperature with an electronic thermometer and looks at it and then leaves the room. And then she comes back again and takes my temperature again, looks at it, leaves the room, and comes back with a mercury thermometer and takes my temperature.

And I'm just like laying, like I can't even form sentences. And she is like, okay, we're going to, you probably have strep throat. We'll test you to make sure, but I'm going to give you antibiotics anyway. You need to take Tylenol or something. She's like, I, your fever is 105.5.5. I didn't believe it. This is why she took my temperature with the mercury thermometer, because she's like, it must be malfunctioning. Yeah. Something's wrong with the electronics. Yeah. And so then she was like sent me

back to my dorm with instructions to do all that. And over, she called the ERs like during the night to see if I had checked in because I was, she was like, she was so worried. She's like, I felt bad about sending you back. And then by the next day I was fine. It was like 97.6. Got to love antibiotics, huh? Antibiotics. I know. That's my fever story. It's a good fever. your story. Thanks, 105.5. Never want to experience that again. It's just below what I said the physiologic set point was, right? Listen, I push it to the max. Take it to the limit one more time. Never again, though. Oh, yeah. Yeah. It's also, I feel like that also like brings up the interesting point of like treating a fever alone versus like if you're giving antibiotics, you're treating the

fever because you're treating the infection, which is causing the fever, right? Right. Yeah. But just like straight antipyretics are not doing that, right? They're just bringing down the fever. So it's interesting. It is. It's interesting.

I feel like I'm going to have more questions for you as we go on. Oh, that sounds great. So, Aaron, tell me, how did we learn? I'm not going to say, like, what is temperature, but like. Oh, God. Yeah. How did we start to measure it? Tell me about the thermometer. I'm thrilled. Thermami. Okay. Let's take a break and then I'll get started. Okay. Well, Aaron. Erin. The history of fever. This is not what I told you that I was going to research initially, not what we were like, oh, we'll do this episode on thermometers and it'll be medical invention really cool. And like, that is really cool and really interesting. Yeah. And I thought, okay. okay, I started out reading and being like, how did we even begin to conceptualize temperature and then to create this tool to measure it where we needed fixed points?

Like, because you can't just, like, how do you know what 90 degrees is? Yeah. Right? Like compared to what? Right. Exactly. So like what is the set? You know, these different fixed points.

And then there's like the whole standardization thing, all of that. So like how do you do that across? the world. I mean, we still don't, right? Celsius, Fahrenheit, Kelvin. Right, but we can, we can, like, communicate among those. Like, we can, like, what do you call it? Calculate.

Translate, yeah. That's not the right word, but. Yeah, what is it? It doesn't matter. Convert. Convert. Thank you. I was like, calculate, translate.

Somewhere in there. But, yeah, I mean, like, how? do you standardize that those temperatures like and so even if you're talking about the freezing point of water or the boiling point of water there is down the rabbit hole turns out boiling is not as simple as you would think it would be because it's like there were entire decades of arguments about like no water is boiling when it looks like this no water is boiling when it looks like this and then you can super heat water so that it actually is higher than 100 degrees Celsius, which is the boiling point of water. But then like at what point does it turn into steam? Is it still we? Well, and like what

atmosphere are you at? Right. In Denver, it boils lower, like at a lower temperature. So I, I quickly was like, this is not for me. I am not equipped to do this. But I do, you know, I wrote this whole intro thing where I was like, it's so amazing that we have these thermometers because, and it is really cool. Like what was life like before we had standardized measurements? Like nowadays, I can be like, Erin, what's the temperature in San Diego? How much does your dog weigh? Can you send me that recipe for espresso fudge cheesecake so I can see if I have enough cream cheese to make it?

Sure can. Three bricks. But we can understand and relate to one another. and the world around us because we have those standardized units. You can say to me, oh, it takes two cups of cream cheese, which that sounds like an awful lot, but maybe that's accurate. Okay. Well, instead of like, I don't know, two scoopfuls of this bowl that I have in my house,

how much does your dog weigh? I don't know, kind of heavy, but I can lift him. It's like that kind of thing, right? Yeah. And so before it would be like, oh, the castle is three days by horseback. And like, what kind of horse do you have? Is it fast? Is it a broken foot?

Yeah. Is it carrying something? Are you dragging something? Yeah. Exactly. Exactly. And so these standardized units are really cool because they help us navigate the world. And also really important in science, of course.

Like we can, it's so crucial for us to be able to replicate scientific studies being like 0.5 mils, whatever. Yeah. But then, you know, the boiling and superheating. I was like, this is, I can't, I can't do this. I'm out of my depth. So then I went back to the drawing board and I was like, okay, what about like the medical use of thermometers? When did we decide that we needed to use those? And then that kind of led me down into what are fevers and the history of fever from capital F fever to fever the symptom. And I wanted to kind of like, take this approach by looking at like, what does fever mean to someone in, to Hippocrates at all?

What did fever mean to someone in the 1700s? What did fever mean to someone in the early 1900s? Like, those things are very different. And then I want to kind of incorporate the use of the thermometer in clinical medicine. Love it. That's what I did. Okay. I love it. So long intro. But a fever started out, at least as far as we can tell, as a cluster of symptoms, kind of as a disease in its own right, or as a frequently encountered state of being. Like it wasn't something that was like super rare. And I will say that if you want like a very full comprehensive history of fever and all of its metaphors, the book that I used for this is called More Than Hot.

a short history of fever. It's by Christopher Hamlin. And yeah, there's a lot more information that I ever anticipated in there. But in ancient Greece and Rome, fevers were, like I said, kind of the state of being, brought on often by external factors not necessarily tied to specific disease. Like working out too hard when it's hot outside could lead to a fever. You're overheating. Your body might feel like warm to the touch.

and your sweat is cooling you down. And so then if you stop working out, that could lead to chills. Sure. Sure. And then there were fevers associated with epidemics of what we now know to be infectious diseases. Those were kind of more on the periphery of things. Like they happened, but they weren't as much of an everyday part of life as something like this, you know, exerting yourself fever, I guess. Interesting.

Sushruda, so the ancient Indian medical scholar from around the 700s BC. described fever as the quote unquote lord of ailment king of all bodily distempers in as much as it can affect the whole organism at one time quote an indispen I have a lot of quotes an indispensable condition under which a creature can come into being or depart from this life hmm I think that's kind of interesting I don't want to give the impression that fevers were not indistinguishable in ancient times because they were people did recognize that certain fevers followed certain patterns, like malaria, for instance. So there were many ancient medical texts from China and India and Greece that like characterize

malaria or other fevers that seem to follow this like every three days or every, you know, however it is this pattern or those fevers that tend to appear during certain times of year or those that appear after wounds like putrid fevers. and the prognosis was different for each of these different kinds of fevers. But the fever was the disease. Do you know what I mean? Yeah. It was a putrid fever.

It wasn't like, oh, that fever is really high because he has a wound and that wound is clearly infected. No, it was like the he has fever. The whole state of being, capital F. Yeah. And those make sense. I feel like those, that characterization makes sense to us today. But what I think is a little bit more challenging to grapple with, at least in terms of what we know now, is something like this passage from the Hippocratic text, which kind of brings into question like, wait, what is fever? Quote, fevers.

Some are pungent to the touch. Some gentle. Some are not pungent, but increasing. Some are sharp, but decreasing to the touch. Some are straightaway burning hot, and some are faint throughout. Some dry, some salty, some with blisters dreadful to see, some damp to the touch. Some are red, some livid, some yellow, and so on. End quote.

It's almost like they're just using the word fever to mean infection, right? Or am I missing it? Yes. No, I don't think you're missing it. But I also don't know, like, I feel like what we're having a hard time doing is like putting that in our current framework of understanding of disease. And it's hard to make parallels with that. And so it is, it is sort of like infection, but also fevers, like when we think of fevers today, they're an indicator. It's like in your car, like in check engine like going on.

Like there's something that might be a miss here. And we're not super concerned about the fevers themselves. It's more about like the overall infection. But for the most part, we have a strategy with how to handle it. And this was less so. Like fevers were much more amorphous. I don't know. It's like it's really hard to wrap my head around.

Yeah. And I think that at least the impression that I get was that, distinguishing which type of fever that someone had, it was important in understanding like the natural history or possible treatments for a disease, but it was less important, at least in ancient Greece in China, than understanding the process of fevers. Because then you have to add on this layer of like the humors and humoral theory of disease and balancing out the humors and how much moisture is in your body or whatever because, okay, you can have putrid fever or you could have like bilious fever or something like that.

And those could be caused by totally different infections. And they could look totally different on the surface. But you would still treat them to balance out the humors. And then the fever schedule also mattered a great deal and was kept track of. Like if someone felt bad on the fourth and seventh day with good days in between, they would probably die. It was almost like, here's your prognosis based on when your fever peaks. And this also lasted like well into the 1800s. It's interesting. And this was in theory supposed to help with intervention, as in like the physician would time their visits to be with the patient

during those more critical periods and providing treatment or maybe a spell, throwback to abracadabra and malaria. But in terms of treatment, if we're going with the humoral theory of disease, Different fevers caused by different imbalances of the humors, which are blood, phleg, black, bile, yellow bile. Most of the time, it was excess of one humor. And so how do you get rid of a humor? Well, if you have too much blood, you bleed them. Let it out. And bleeding really was like a primary treatment for fevers for hundreds of years.

And this also sometimes applied to the prevention of fever, which was dependent upon the cause, which was dependent largely upon the patients themselves. So if the cause was something like, oh, you have too much phleg, then maybe you should hold off on eating this thing or overindulging in this way, that kind of thing. And that also in turn had very personalized to the person's like social status and, you know, class, all of that kind of thing. Just the normal thing that we expect to see. But I also think it's really interesting because this framework of disease that was highly individualized in this way, oh, it's your overwork that caused this humor to increase and this is what you need to do.

All of that was challenged when epidemic fevers appeared. But then those, there's always an explanation. Those could be explained away by society at large is bad and you're all being punished for what you've done. Now go into your room and think about your decisions. or like the bad winds blew into town, whatever. So the concept of fever or the umbrella term of fever, I think is kind of hard to get a handle on, even if you're just looking at one time period like antiquity.

It was recognized to be elevated body temperature, but it was also fever with a capital F, like a collection of symptoms. It could be brought on by everyday events or seasonal contagions. It could be cyclical or follow a totally different schedule. It could represent a horrible deadly disease or just be a symptom of a more mild one. It was caused by an imbalance in the humors or too little moisture in the body or over-exertion or over-indulgence. It was anything. Everything.

All of it. All of it. And over the centuries, these different definitions of fever kind of ebbed and flowed. Some became more popular, fell out of favor, that sort of thing. And as society and science changed, so did. the meaning of fever. So we've already seen this a bit with the onset of fever thought to be caused by like various personality types or lifestyle habits or larger societal issues. But beginning in the 18th century, fever in the quote unquote Western world became less about disease and even more a state of

mind. It's hard from our 21st century vantage point, at least for me, to understand like again what this what this fever then shifted into. So let me give you a couple of examples in quotes of like some of the range of things that a fever could be. Okay. This is from the 18th century. Oh, the first one is about someone who isolated herself, quote, resolved never to think, speak, answer, or hear. She is quite wearied with saying good night and good morning and has almost every day a touch of fever, which a little rest always carries off, end quote. So is that malaise, fatigue, elevated temperature, something else entirely, all three? Like... A touch of fever. And then there's this about somebody else's fever, quote, at the point of death of a violent fever he got with swallowing two glasses of

brandy upon a debauch of wine, end quote. So like, was he really hungover? So he was, he was, had a violent fever from drinking a lot of brandy and wine. Right. I mean, that would make me feel crappy. Right. Does that mean like body aches and vomiting? That is so interesting.

I never thought about, because like I just always assume when I've read old-timey things, if they say the word fever, they mean what we mean. fever. Yeah. Nope. Nope. Nope. And during this period, like the 1700s, the early 1800s, fever seem strongly tied to the brain, either brought on by too much mental work or intense emotions or directly affecting the mind, like someone's fever causing, quote, a loneliness of spirits and falling away that alarm everyone, end quote. And I think that this is all, also really interesting because there is a term, I didn't really get into this too much, but like brain fever is a thing that pops up a lot in Victorian literature. I guess like the Bronte sisters,

Charles Dickens, like Pip and Great Expectations gets brain fever at one point. Catherine from Wuthering Heights gets brain fever, dies of brain fever, spoilers. You're allowed to spoiler. Statute of limitations. But there, you know, Elizabeth Gaskell, there were someone who had a brain fever in one of her books. Like, there is, brain fever was like a trope almost in, in literature from this time, where it was like this emotional shock brought on this fever that could then be very, like, physical manifestation of an emotional shock. It wasn't meningitis. I mean, or maybe it was. Like, it very well could be. Who knows? Who knows? Wow. Okay.

I do think it's really interesting to use popular literature as a lens through which people, everyday people saw like medical understanding from that, like contemporary medical understanding. Yeah. Anyway. Sorry. That's our next book club. Yes. There probably is a book like that. Yeah.

Okay. But also the meaning of fever had to do with your social standing, right? So those who were living in poverty fell victim to contagious fevers. transmitted through unsanitary living conditions or like working too hard, the strenuous physical work. And it was seen as like a societal problem or personal shortcomings. And especially it was like clean it up so that the contagion doesn't affect the rich. And whereas the origin of the upper classes' fevers seem to be much more refined, like too much thinking overindulgence in rich food or wine or. whatever. But this brain fever, which I, like I already mentioned, was very different than like

bilious or putrid fever or remitting fever or tertian fever. And so it was understood that fevers could be caused by many different things and that there were many different types of fevers. And there began to be, I think, a dawning recognition that maybe fever as a symptom was at the core one mechanism, one thing, with degrees of severity and a basis in the nervous system and vascular system malfunctioning. And so fever as a symptom, what I mean by that is, well, it's a little unclear, but like mostly temperature. Yeah. But the question then became, like, how do you measure how severe a fever is, like how dangerous it is? And so since ancient times, physicians had recognized that fever was associated with the body being warmer to the touch than normal.

And sometimes they also observed that the pulse was elevated. One of the earliest pulse measurements was made in the third century BC. Okay. Aaron, how do you measure a pulse? You just count it. Against what, though? Like, what is the unit of pulse rate? Beats per minute.

But how do you measure a minute if you don't have a watch? They didn't have clocks? So the whole clocks. A sun dial? A sundial thing? In this third century BCE, Herophilus used a water clock. I'm not sure how it worked, but it was like presumably you could measure against this, like how many drops of water or how long it took. Like a sand timer thingy, but.

Yeah. Yeah. I didn't think about that. Oh, clocks are because, and then you could use like pendulum. clocks type of thing, but you couldn't use those on ships for navigation because the walk. Right. Right. It's so interesting. Yeah, anyway, I'm not even going to do that. It gets so deep just to be able to measure a fever. Uh-huh. And so in general, although these two characteristics of fever, body temperature and pulse rate, had been recognized since ancient times,

there wasn't a whole lot of effort made to quantify them, at least until around the 17, hundreds. So, okay, we talked about Pulse, right? It was in the 1690s that watches with second hands were introduced. Yeah. I don't know how to feel about that. It feels very early somehow, but I guess I've never thought about when watches were invented. I know. The stuff we take for granted, I'm telling you. Seriously. I'm telling you. Talking to each other on the freaking airway internet. The World Wide Web. Worldwide web.

When has a watch invented? Wow, 1690 with second hands. Okay. Mm-hmm. Mm-hmm. I mean, so before then, there were other, like, clocks or ways of measuring time, but they weren't widely available or widely recognized to be useful in medicine. Okay.

And so in 1707, Sir John Foyer wrote about his observations. of pulse rate measured against a watch, quote, our life consists in the circulation of blood, and that running too fast or slow produces most of our diseases. The physician's business is to regulate the circulation and to keep it in a moderate degree. I don't know how he expected to do that. But that was his job.

His job. And so with the introduction of the 60-second watch, pulse rate kind of took center stage in terms of diagnosing a fever by the 17th century. So it was like a fever was not temperature. It was pulse rate. Right. Okay. That's interesting.

Yeah. But pulse rate is not ideal for this. Like your pulse can rapidly change if you're active, if you get stressed, it can go up or down without a corresponding change in body temperature. So it became apparent that like pulses could not be relied upon for like every sort of diagnosis. If only there was something that could quantify, something like body heat, right? And the thing is, by the 1700s, thermometers had already been developed. So I love this, this is a quote by Thomas Willis from 1692 about using pulse to diagnose fever. This is about pulse.

Quote, first we consult the pulse as a thermometer constituted by nature for measuring the heat kindled in a fever. End quote. So they had the word thermometer and they have thermometers, but they're like, the pulse. The pulse is the thermometer. It is nature's thermometer. Isn't that amazing? That is fascinating. Yeah.

So clearly people knew what thermometers were by this point. What kept them from being used in a medical setting? So the broader history of thermometers, like I said, is too much for me to get into. But I do want to focus on when they were first used medically. So people had been toying around with measuring temperature for centuries. But most histories put Galileo's invention of the thermoscope around 1595 as the first major advance in measuring temperature since ancient times. Yeah. Yeah. 1590. That is a lot earlier than I thought, Aaron. I don't know anything about history.

We've done this for so long and this blows my mind like, oh, it's embarrassing. It's not. It's like, I mean, it's really hard to put this in context. Yeah. I don't know. Yeah. I also don't know how the thermoscope worked. So, and how different it was to thermometers. But, but in the decades that followed, people did try to use various thermometers or thermometer-like instruments to measure human body temperature. So like somebody would be holding the bulb end of a thermometer in their hands or popping it in their mouth.

But these methods and the measurements produced were pretty crude and certainly not fine enough to make any meaningful connection between fever. severity or even establishing a baseline. Okay. Like I feel like especially when we're talking about a fever being 100 point, no, 101, excuse me. 100.4. 100.4. 101 if you're in the ICU.

Okay, okay. But like that's not very far off from some of the extreme temperatures that you could measure from just like air, ground, whatever, water. Go to Arizona. Yeah, exactly. And so there really needed to be a lot more work done to, like, establish a baseline and create instruments that had more fine, where you could actually, like, measure more finely. And so in 1714, Gabriel Fahrenheit, like, guess what he did?

No one. He was the one, the chosen one. He invented the mercury thermometer. I don't know anything else about him, so I don't know if he was indeed the chosen one. But 1714, right? Okay. Thermometer. And despite how revolutionary this tool could have been, has been for medicine, some

people did point that out. It didn't really take off very quickly. So some people, like the Austrian physician Anton DeHan, took extensive measurements of both temperature and pulse of people of varying ages with varying health throughout the day, changes in temperature or pulse after activity or certain drugs. He was a firm believer that the physician's hand, assessing fever would no longer suffice, thermometer only from here on out. But he scattered his observations that he had made, these tons of observations throughout a massive treatise that he published

in the second half of the 1700s. And so it was just like way too long for anyone to actually make any sense of. So it kind of just skipped. Yeah. And I think that like it is still, from this vantage point, it is a little bit baffling to be like, here's this obvious tool that could be so helpful. How do you not see it? It is literally a part of every physician interaction pretty much or like go to a doctor's office. You're going to get your temperature taken. But I think that we have to keep in mind a few things. So it wasn't that people didn't care about quantifying previously subjective things. Like that was very much in style in this time. In the mid-1600s, the Royal Society stated that they want to bring, quote, all things as near the

mathematical plainness as they can, end quote. But medicine kind of considered, was considered to be separate from science at this point in history, from the 1700s into the 1800s. I've seen it described as science wanting to use these new measuring devices to better understand the world around them, whereas medicine was more concerned with a cure, with testing therapies on fever rather than understanding and characterizing fever. So you have people like Benjamin Franklin, like very much like scientists, observing that human body temperature stayed the same despite the weather outside, but not necessarily measuring the body temperature, you know, in someone who had smallpox or plague or something like that, yellow fever. Plus, it was harder to conduct experiments

on the mechanism of fever than on possible treatments. The other major factor in this delay was in the thermometers themselves, which still had a long way to go in terms of standardization or quality control. So people would get recordings of 118 degrees Fahrenheit, like body temperature recordings of 118, 122. And the person would be like, I'm okay. Like, I'm just chilling. I don't know. I don't know. I don't know what I did. So you can imagine being a physician looking at this reading and going, this person shouldn't be alive if this thermometer is right. So like this thing is useless. I'm not going to use it anymore. And so thermometer accuracy did get better. And in 1835, the mean body temp of a healthy adult was established to be 98.6. The last bit of the recipe

is just preconceived notions. If you think you knew how fevers worked or even what a fever was, then you're going to be less likely to investigate whether you were right. Like we just take this knowledge for granted and we're like, yeah, of course it's that. Of course this fever is caused by X, Y, and Z. We don't need to measure the body temperature because it's the pulse rate. Or we don't need to measure the body temperature because I took a full patient history and they seem to have brain fever. Yeah. And so it took until around the mid-1800s for enough curiosity or doubt or need or

knowledge to emerge to get people to reconsider how fevers worked and conclude that body temperature is actually a much better clinical guide for fevers than pulse. And it was then quickly integrated across medical practice. So for instance, before the mid-19th century, patient records at Mass General included pulse and respiratory rates, but only some of them had those, like not all patients had these things, no other quantitative metric at all. By the 1880s, though, you've got daily pulse, temperature, and respiratory rate being charted. The thermometer was here to stay. And the knowledge that it generated was exponentially increased by all of the other scientific achievements or advancements happening during the 1800s, the laws of thermodynamics,

discoveries of antipyretics, germ theory, showing that different fevers could be caused by different pathogens. Comparing temperature and pulse between typhus and typhoid, for instance, even before germ theory was able to distinguish between the two, just looking at temperature and pulse could say, that's typhoid, that's typhus. Because of the pulse temperature dysregulation that happens in typhoid, check our episode. Uh-huh. It's a really thrilling.

And so all of this helped to transform fever, capital F, the disease, into fever, the symptom, from the whole diagnosis to just a data point. It was a huge shift in how diseases were perceived and managed. The individual personality or lifestyle habits like overwork or a troubled mind, particularly among the wealthy, were no longer seen to be the leading cause of fever. I was trying to think of what the opposite of a silver lining is. Is it just like the gray cloud across the sun? I think so.

Okay. That's what this is. Thermometers began to show that what a patient felt might not be fact. So you know what we talked about when you're shivering and you're like, no, I'm really cold. I'm piling the blankets on. Doctors could take your temperature and be like, you're not cold. You're hot. You don't understand what you're feeling.

Oh, dear. Yeah. I mean, and so this is one of the less extreme examples, but the author of this book, Christopher Hamlin, wrote this little quote that I really enjoyed, where he said for a patient, quote, a century earlier, fever or feverishness would have referred to a state of feeling akin to a modern mood disorder. One expected a physician to assess its type and probably coarse and then suggest the best response, not sanction its existence, end quote. So all in all, obviously, temperatures or thermometers were an incredibly valuable thing. And if we only had ways to objectively measure many other things, I feel like we could really advance treatment and care for people. But what we see happening with temperature and thermometer in the 20th century, the late 1800s

and into the 20th century is the trivialization and domestication of fever. medications became available to bring a fever down, and most households began to have a mercury thermometer at home and these medications. So if someone had a fever, you just took care of it at home or you monitored it at home until it got worse, whereas in the past you would probably have a doctor to make a house visitor. You would take someone to a doctor. But the story of the fever isn't over. It's almost over.

Don't worry about it. Because once capital F fever became lowercase fever. people began to wonder why this response existed. Kind of like what we talked about and whether it could be beneficial. And so fever as a response to infection was found to be super widespread across the animal kingdom. And so some researchers took this friend not foe idea and ran with it, maybe a little too far, developing something called fever therapy cabinets in the early 20th century, where they would treat infections like syphilis that did not include.

fevers by locking someone's body in a cabinet with just their head poking out and they would crank up the heat until their body temperature got to like 106, 107. Which is not a fever. That's just hyperthermia. Yeah. Yeah. Great idea. It's called fever therapy, Aaron.

Get with the program. Uh-uh. I object. Would you like this next program? Because. Oh, dear. I think I've mentioned this before. In 1927, the Nobel Prize.

Prize for physiology or medicine was awarded to Julius Wagner Yareg, who treated cases of neurocifilis by infecting his patients with the malaria parasite, a malaria parasite. Yeah. You got a Nobel Prize for that? Uh-huh. I should have checked to see whether it worked. I assume it did. Yeah.

I would assume you get the Nobel Prize for it. Yeah. It's kind of interesting. Anyway. And so this debate, you know, is fever friend? Is it foe? Is it like the casual acquaintance that you met that one time and you don't really ever think about? And it's just kind of like there in the background. I feel like that debate is still going on like we talked about. But yeah, I mean, I think like I said, I think that the thermometer, it was really one of those things where I was like, if only we could measure pain in this way. Because once we develop the thermometer and we're able to use it in clinical medicine, then we could much better test things like, does quineine actually bring down your fever? You know, does aspirin bring down your fever?

How does it bring it down? How, when should we administer it? What are the different courses of these things? Just like, because I think we're always down on quantifying symptoms and being like, oh, objective symptoms are or objective signs of a disease are leaned on very heavily by modern medicine at the cost of the whole person and like the other things that they're experiencing that are harder to describe. Right.

And I think that's valid. But I also think that like would be beneficial to have all of the things. A hundred. A hundred percent. Yeah. Yeah. I agree. So there's a lot more to learn about fevers and especially about like the evolutionary side of

fevers if you want to go into that and like evolutionary medicine, it is an interesting field. When you mention something about iron. Yeah, iron, sedaraphores. I was like, we're going to have to do hemacromatosis. Oh, it's on our list. I think it's like early in the season. Oh, sweet. Yeah, it's already like on our schedule.

Perfect. I should check our schedule. And if you would like to check our sources. You can. Let's do it. Okay. I already mentioned Bine. What is it? A Short History of Fever, more than hot, a short history of fever by Christopher Hamlin. I have a bunch of other papers, too, that I'll post up there. I had just a few papers that I used for this episode, actually. One, if you want really fun, deep dives, I have some really, really fun ones. This one was

called the Physiology of Mammalian Temperature Homeostasis, and I already have like three of pages of notes that we didn't even get into about like bears and hibernation and blubber. And like we, it does make you want to do a whole episode on temperature homeases, but tell us if that sounds too boring listeners because like I could go off. And then I also have a couple on like there was one by Walter at all from 2016. That was a pathophysiological basis and consequences of fever. That was a really good primer on fevers. And a few more.

We'll post the links for all of our sources from this episode and all of our episodes on our website. This podcast will kill you.com under the episode. tab. We will. Thank you to Bloodmobile for providing the music for this episode and all of our episodes. Thank you to Tom and Leana for the wonderful audio mixing. Thank you to exactly right. And thank you to you listeners. We had a lot of fun with this episode. Yes. I actually really loved this. Me too. It was super fun. And a big thank you as always to our wondrously generous patrons. We appreciate your support. So,

very much. Thank you. Thank you. Thank you. I've been recording so many of these book club outros that I forget. Oh, yeah. Wash your hands. You filthy animals. This is Special Agent Regal. Special Agent Bradley Hall. In 2018, the FBI took down a ring of spies working for China's Ministry of State Security,

one of the most mysterious intelligence agencies in the world. The Sixth Bureau podcast is a story of the inner working to the MSS and how one man's ambition and mistakes opened its fault of secrets. Listen to the Sixth Bureau on the IHeart Radio app, Apple Podcasts, or wherever you get your podcasts. I'm Amanda Knox, and in the new podcast, Doubt, the case of Lucy Letby, we unpack the story of an unimaginable tragedy that gripped the UK in 2023. But what if we didn't get the whole story? Evidence has been made to fit. The moment you look at the whole picture, the case collapsed. What if the truth was disguised by a story we chose to believe?

Oh my God, I think she might be innocent. Listen to Doubt, the case of Lucy Lettby on the IHeartRadio app, Apple Podcasts, or wherever you get your podcasts. I'm Clayton Eckerd. In 2022, I was the lead of ABC's The Bachelor. But here's the thing. Bachelor fans hated him. If I could press a button and rewind it all I would. That's when his life took a disturbing turn.

A one-night stand would end in a court. room. The media is here. This case has gone viral. The dating contract. Agree to date me, but I'm also suing you. This is unlike anything I've ever seen before. I'm Stephanie Young.

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