It’s every coffee drinker’s worst nightmare. You’ve rushed to that important morning meeting, but everything’s feeling a little hazy. You’re struggling to concentrate, and a nagging headache starts to creep in before you know it.
Then it hits you — you haven’t had your daily caffeine fix!
So what is it about this mysterious substance that can derail your whole day if you don’t have it? In a bid to find out, James conducts a cruel experiment with Scott and Jools, depriving them of coffee for 24 hours.
Producer man James bothers clever people to get to the bottom of what caffeine is and what it does to our bodies and brains!
Danielle Gulick from the Morsani College of Medicine explains how your morning cup can change your thinking. Lindsy Kass from the University of Hertfordshire tells us how some people can get away with a double espresso right before bed. Professor Jonathan Morris reveals how it’s not just humans who get a buzz from caffeine.
Ultimately we seek to find out: Do we really need to worry that an extra cup of coffee could be the end of us?
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Join our Patreon to support the show and win a free premium hand grinder! https://bit.ly/3vrispx
Check out our wonderful caffeine experts online, including Lindsy Kass’ on Twitter (https://bit.ly/3Ou0k7y), Danielle Gulick (https://bit.ly/3K3Xpzh) and Jonathan Morris on Instagram (https://bit.ly/37eMS3F).
Listen to the A History of Coffee podcast (https://bit.ly/2NArChO) and read Jonathan’s book, Coffee: A Global History (https://amzn.to/3dihAfU).
Follow Sibling Cafe in Cardiff (https://bit.ly/3L4YDLQ) on Instagram and taste Perky Blender’s decaf produced by Angele Ciza in Burundi (https://bit.ly/3rGPlOr)
Learn more about the Siemens EQ700 fully automatic espresso machine: https://bit.ly/3Ia8yy5
Find your perfect roast with the Ikawa Home: https://bit.ly/3IdYVPc
Tell your local barista about Adventures in Coffee!
Our Instagram handles:
James Harper / Filter Stories: https://bit.ly/2Mlkk0O
Jools Walker / Lady Velo: http://bit.ly/39VRGew
Scott Bentley / Caffeine Magazine: https://bit.ly/3oijQ91
James Harper: Welcome to Adventures in Coffee, a podcast about the mind melting, heart pumping world of coffee, brought to you by IKAWA Home and Siemens Home Appliances.
Jools Walker: Now here on Adventures in Coffee, we love to serve you surprising coffee stories to open up your taste buds and your mind.
Scott Bentley: And we hope to inspire you to have coffee adventures of your very own.
James Harper: Now I'm James Harper, professional storyteller, coffee lover, and the founder of the coffee podcast, Filter Stories.
Jools Walker: And I'm Jools Walker, also known as Lady Velo on other parts of the internet. I am a best-selling cycling author, digital content creator, and your very everyday coffee lover.
Scott Bentley: And I'm Scott Bentley. I'm the founder of Caffeine magazine. I'm an art director and brand strategist, and an all round coffee nerd.
James Harper: So, Scott, Jools, the other day I played a rather cruel experiment on you both.
Scott Bentley: You did James!
Jools Walker: Yeah, experiment / torture, I think you'll find.
Scott Bentley: Yeah. Thanks. That was a pretty low point in my life.
James Harper: Listen, I think I need to add some context here, because I don't know what the listener thinks that I was doing to you, but literally all it was, all I asked you to do, was not drink coffee for 24 hours. And Jools, remember, I recorded a conversation between us.
Jools Walker: Oh, yes, indeed.
James Harper: OK, so this is the second attempt, here. We just had a wonderful conversation, really good tape, but unfortunately, because I didn't have any caffeine, I forgot to press the record button. So here we go again. Alright, Jools, where are we?
Jools Walker: We are at the Truman Brewery in East London, getting ready to set up for the London Coffee Festival.
James Harper: My last drop of caffeine, coffee, was 11:00 a.m. yesterday morning. It is now 10 a.m. So it's been almost 24 hours. And, how are you feeling now that caffeine is fully out of your system?
Jools Walker: I'm feeling slightly tired. It does feel kind of hazy, and I feel, I wouldn't say relaxed. I think just sedate, yeah.
James Harper: That is the right word, sedate. It’s like I've had a painkiller or something. and I'm just kind of foggy.
Jools Walker: Yeah. I just feel like I need something to lift the fog.
James Harper: So, you know, a few hours have passed and at the show we'd finished, you know, putting some tables together and stacking them full of Caffeine mags, which we were then going to spend the weekend giving away.
Jools Walker: Oh God, I felt lost. My soul was missing something and that something was caffeine, and it did not feel great now that I think back to it.
James Harper: And when I busted out the microphone, that was pretty obvious.
Alright Jools, we've just finished setting up the Caffeine stand. You are yawning. That was a long, big yawn. How are you feeling?
Jools Walker: I mean, I'm feeling like I'm in need of something containing caffeine at this point. It's, where are we now? It's nearly quarter past 12. I've had no coffee. It almost feels a bit torturous considering where we are and watching people setting up coffee machines.
Yeah. That was troublesome for me. Just knowing that you were surrounded by all that delicious, lovely, unctuous coffee, and none was for us. None.
James Harper: Sorry.
Jools Walker: Wicked boy.
Scott Bentley: Oh, James, I’ve got to say, by that point I was on my knees. And I needed something.
James Harper: Yeah, Scott, I hadn't recorded you really much, but like an hour later, after we finished setting up the stand, we went to a local coffee shop.
Scott Bentley: I've definitely started to get a bit of a headache. It feels like it's quite in the front. But yeah, I am hankering for a coffee.
Jools Walker: I have a slight headache coming on as well. If you want specifics, it's actually this part, the right side of my head,
Scott Bentley: We obviously weren’t feeling that great. How were you feeling?
James Harper: I was so depressed.
It's like, I don't even care about anything right now. I just don't care. I'm just zoned out of life. You know, there could be a nuclear apocalypse right now, and I'd be like, all right, it is what it is.
Jools Walker: And it's not even like you were angry, done. You were just finished. That was it. I've never seen you so muted before.
James Harper: I’d lost the will to live, frankly.
And then after all of this, we ordered some coffees at this cafe and took a sip.
Scott Bentley: Shout out to WatchHouse, by the way, they were great coffees.
James Harper: And Scott, I'll never forget the sound you made when you took that first sip of coffee.
Scott Bentley: Oh, dreamy.
James Harper: And as soon as we had that sip of coffee, everything just magically fixed itself.
Scott Bentley: I actually definitely feel clearer. I didn't feel like I had a real fog over me, but I do feel now there's an added clarity.
James Harper: I can just say on my side, I'm feeling super alert, imaginative, focused — I'm ready to tackle the world again.
Scott Bentley: It's like when you go into Photoshop and you just click on the sharpen button, everything just sharpened up a bit.
Jools Walker: I now have to ask you, what was the point of putting us through all of that pain, James?
Scott Bentley: Yeah, James.
James Harper: My own sadistic pleasure. That's all it was.
Scott Bentley: It probably was!
James Harper: What that experience proved to me, anyway, is that a) caffeine is absolutely a drug. And b) it has a massive effect on us.
And this drug caffeine has got me really curious. Like, what precisely is happening in our brains and our bodies as soon as caffeine enters our blood? Because I spoke to a bunch of scientists and experts and learnt that actually caffeine is doing a load of things in our buddies — a real cocktail of different things.
Jools Walker: I want to know why on earth I was feeling as terrible as I was for something as simple as not having coffee for 24 hours.
James Harper: So yes, I will cover all of that in the second half of the episode. But in the first half, I want to kind of lay out some surprising facts about caffeine and maybe where it crops up in nature, and on your high street.
Scott Bentley: Yeah. Looking forward to finding out… Well, I think I'm looking forward to finding out. I think I am…
James Harper: You are looking forward to finding out, trust me!
Jools Walker: Alright, but James, before you take us on this magical mystery journey, let's hear a quick word from our sponsors.
And it's time to take a coffee trip with Siemens Home Appliances.
Scott Bentley: Great, where are we off to today, Jools?
Jools Walker: Scott, I am taking you to one of the oldest countries in east Africa, Burundi.
Scott Bentley: Tell me why you've chosen this one.
Jools Walker: Well, here's the thing about Burundi: About 80% of the coffee growers in the country are women. But female entrepreneurship is still kind of rare. But this particular coffee that I've chosen for us today is a result of a powerhouse of a woman, Angel Caesar. Now, she's a Burundi native who about 10 years ago got into the coffee business with a friend of hers, and they purchased a number of washing stations.
Scott Bentley: Washing stations are essentially the places where you process coffee, not where you grow it.
Jools Walker: And this specific coffee that we're having today is called the Refecker Project and it's designed to combat poverty and support women who produce coffee in the country.
Scott Bentley: Awesome. Sounds great. Come on, let's drink it.
Jools Walker: Here's the kicker. It's a decaf.
Scott Bentley: Oh.
Jools Walker: Don't be like that. Don't be like that at all.
Scott Bentley: OK, I’ll reserve judgment. Let's whack it in the EQ700.
Jools Walker: So, I'm going to swipe across to the latte macchiato option, and I'm going to make this one strong at 250 mils and I’m going to have an 80% milk ratio for it.
This is with almond milk,
Scott Bentley: This was actually roasted by our very good friend Francoise Knopes at Perky Blenders. But, Jools, what are you tasting in the cup?
Jools Walker: Well, I'm tasting a sweetness, like a sort of brown sugary sweetness to it.
Scott Bentley: I'm definitely getting sweet, sugary, but it's brown sugar, not a white sugar. And you can drink this anytime you like. It's decaf!
Jools Walker: Well, you could be on it all night, if you wanted to.
Scott Bentley: And that was a coffee trip brought to you by Siemens Home Appliances.
Jools Walker: So James, this is a pretty big journey, I feel like, that we're going to go on. But I have to ask: Where does caffeine actually come from?
James Harper: It’s found in a number of plants.
Scott Bentley: Yeah, the way I understood it, I thought it was a sort of insecticide. It was a compound that the plant produces to stop insects feeding on it, essentially.
Jools Walker: OK, well, when you put it like that, that now makes me think that caffeine kind of equals poison. So that can't really be that good for me, or anybody. This is dark!
James Harper: Everyone relax, everybody relax. Here's the thing: No one really knows for sure why plants produce caffeine. And the theory that caffeine is an insecticide is still actually quite popular.
Danielle Gulick: High concentrations. It can actually protect the plant as well. They do need to consume a fairly large amount for it to actually be lethal.
James Harper: This expert, by the way, her name is Danielle Gulick.
Danielle Gulick: I am an assistant professor in the Department of Molecular Medicine at the University of South Florida Morsani School of Medicine.
James Harper: So there's that. But there have been some quite interesting findings of late. And I also spoke with resident historian of the show, professor Jonathan Morris. He wrote the book Coffee: A Global History, and with me, we produced the podcast series, A History of Coffee. And he filled me in on a study.
Jonathan Morris: So, one of the things that someone has done recently, is they looked at what attracts bees to certain kinds of nectar in plants. And it transpires that bees more frequently frequent plants that are giving them a little caffeine kick with their nectar. So in other words, the bees are also getting a buzz from caffeine.
James Harper: How long have you been waiting to say that one?
Jonathan Morris: Actually, I only just thought of that. I'm very happy with it!
Scott Bentley: Has Jonathan thought of doing standup?
James Harper: He was on form that day. He really was.
Jools Walker: So, it seems like from this, that caffeine is used for a variety of things, you know, like it's a multi-purpose substance.
James Harper: Yeah, absolutely. You know, for some things it's an insecticide, for other things it's a stimulant. But the idea that caffeine is just like this poison, I mean, that's a very simplistic, narrow way of seeing the natural world, in my opinion.
Speaking of lethality, how much do you both weigh?
Scott Bentley: That's a rude question to ask a lady! On a good day, I would put myself at 80 kilos, but I'm probably far from a good day. Let's just say 85 kilos.
Jools Walker: I am 66 kilograms.
James Harper: I’m 80. So let's take a halfway house. Let's say 75 kilos, maybe the average person. OK, here's a question for you: How many KitKats would you have to eat to die from the caffeine content in the KitKats alone?
Jools Walker: KitKat chocolate bars?
James Harper: Correct.
Scott Bentley: I think you would die of other things before the caffeine.
James Harper: Of course you would. Of course you would. But just the caffeine alone.
Scott Bentley: Just the caffeine in a KitKat? A hundred KitKats — I'm sure it's not.
Jools Walker: I'm going to be, like, 600 KitKats.
James Harper: So get this. There’s this website called caffeineinformer.com and they have this tool called Death by Caffeine. And you put in your weight — so 75 kilos — choose the food you want to die from caffeine by — KitKat — and the answer: 1,880.
Scott Bentley: Wow. OK. Alright. Just to baseline it.
Jools Walker: Yeah.
James Harper: How many Cliff energy bars would you have to eat to die from the caffeine content alone?
Jools Walker: Two and a half thousand Cliff bars to kill you.
Scott Bentley: I reckon that they are going to have more caffeine in, so I’m going for half, I'm going for a thousand Cliff bars.
James Harper: 230.
Scott Bentley: OK, surprising!
Jools Walker: No!
James Harper: OK, let's continue, shall we? How many cups of tea would you have to drink to die of the caffeine?
Jools Walker: Um, 750 cups.
Scott Bentley: What? Are you having a giraffe? I'm literally going, like, 30.
James Harper: 267.
Jools Walker: Oh, I need to slow down on my tea sessions,
Scott Bentley: What, are you knocking on close to 200, then?
Jools Walker: Two hundred a day, just sat down in the living room. Just drinking tea. I'm blown away at the idea that caffeine is found in so many food stuffs. So, as soon as you said KitKat, I was like: What? Maybe it's silly of me to say this out loud, but I don't think about caffeine when I'm eating chocolate or eating a KitKat.
James Harper: In fairness, very low amounts, but it's still there.
Scott Bentley: Are you going to get us to the coffee one yet? You need to be specific about the coffee as well.
James Harper: I’ll give you specific!
Jools Walker: I'll give you specific.
Scott Bentley: I'll give you specific.
James Harper: How many Nespresso capsules?
Scott Bentley: OK, I'm going back to 30.
Jools Walker: I'm going to say a hundred.
James Harper: 188.
Scott Bentley: Oh, not that much less than the tea, really.
James Harper: OK. A Starbucks grande cappuccino.
Jools Walker: I'm going to say 70.
Scott Bentley: I'm going 60.
Jools Walker: Oh, it's 10 between us.
James Harper: Good guesses. Jools, you're closer: 75.
Jools Walker: Oh.
James Harper: Now, Costa latte, from Costa Coffee.
Scott Bentley: Would that not be the same?
Jools Walker: That's what I was just thinking. This feels like a trick question, or…
James Harper: I’ll give you the answer straight away. So, Starbucks was 75, Costa Coffee, 40.
Jools Walker: OK, that's a massive jump between the two. And even if they are two completely different high street brands, I just would have expected them to be the same.
Scott Bentley: And also, I mean, you think about how much coffee you can fit into a portafilter, which is that handle they put into a coffee machine, they don't vary that much. I mean, they may be 17, 18 grams, but it's not like nearly double the amount of coffee they're putting in. Well, actually Scott, to that point, a study was done a number of years ago, which I spoke to Jonathan Morris about, and he explained why there's so much more caffeine in different high street coffees.
Jonathan Morris: So there was this survey that was done of what did you get if you asked for a single espresso in Glasgow in 2012? And from the serving size range, you'd get anything from 23 millimeters up to 100 milliliters.
James Harper: Wow.
Jonathan Morris: And from the caffeine content, you’d have got anything from 51 milligrams to 322 milligrams.
Jools Walker: It’s the differences between the doses.
Scott Bentley: It does sound though, James, that if you go to one coffee shop, rather than another coffee shop, you know. you have a lovely little coffee with some friends, you maybe have a second, you maybe take a third out — by the end of this, you're going to be shaking like a pooping dog.
James Harper: Listen, everybody here just needs to calm down, take a deep breath, especially the dog. Scott, you make it sound as if you're about to drink one coffee too many and that's going to be the end of you. But the fact is, it's really difficult to drink so much coffee that you're actually going to hurt yourself for one simple reason.
Danielle Gulick: You're going to be full up long before you hit your tolerance for caffeine.
James Harper: And if you were curious, what would actually happen if, somehow, you decided to chug liter upon liter upon liter of coffee, here are some more reasons why it's going to be really hard for you to continue drinking.
Danielle Gulick: So, your heart will be racing. Your muscles will be so jittery that you can't sit still. Most likely, in a large amount, you will probably have a splitting headache. So all of these effects will start compiling and you certainly would not continue drinking at that point.
Jools Walker: Alright, so how much is the recommended dosage for caffeine?
Danielle Gulick: So, most medical groups recommend that, depending on your body mass, five cups is really the maximum that they would recommend on a daily basis. That's somewhere around, say, 500 milligrams of caffeine.
Jools Walker: Oh, I don't think I could do five cups a day. We've talked about this in previous episodes, but I think two is the maximum for me that I can take.
James Harper: And Jools, that's actually quite interesting, because another thing I learned is that there are quite big differences between how different people react to caffeine.
Lindsy Kass: Ten percent of the population, they reckon, is not affected by caffeine at all. And then roughly 5% are hypersensitive to it.
James Harper: By the way, this is another research I spoke with.
Lindsy Kass: So, my name is Dr. Lindsy Kass, and I work at the University of Hertfordshire, principal lecturer in Sport and Exercise Science.
Jools Walker: OK, so we’re saying that there are some people that are just not affected by it at all. So, is that why you've got people out there that can down a double espresso before going to bed and not feel the effects? They're not going to be wired.
James Harper: I'm so envious of them, yes, that might be the case. That might be why.
Scott Bentley: But then, is that also not after they've also had a three-course dinner, massive amounts of meat or something like that? And there is nothing to get them out of that food coma.
James Harper: Absolutely, that plays a part as well.
Jools Walker: This has got me pretty curious. Because I now want to know more about, you know, the effects that caffeine has on our bodies. Like, when I'm drinking it, what is it actually doing to my insides?
James Harper: Well, Jools, maybe now is the right time to dive into the mind melting and heart pumping world of caffeine interacting with our bodies.
Scott Bentley: You really are opening a can of worms.
But look guys, before we get there, let's just have a quick word from our sponsors.
Scott Bentley: So, Jools, can you, an everyday coffee lover, roast coffee like an expert on the IKAWA Home.
Jools Walker: Prepare yourself, Scott. The other day, I roasted up another batch from Buie Bora. Now, she's a female farmer in Ethiopia with three acres of land in the famed Yirgacheffe region.
Now, I quite liked the recipe that I used the other week. So I tapped it in again on the IKAWA Home using the app, and it automatically roasted up the coffee and I shipped it off to a shop in Wales,
William Sibling: I'm Will. I just recently opened a coffee shop and wine bar in Cardiff with my sister.
Jools Walker: Now, Scott, does the name Will and his sister, Georgie Thomas mean anything to you?
Scott Bentley: Um, should I know them?
Jools Walker: Well, yes, Scott, you should. They are the 2019 Welsh aeropress champions in first and second place respectively.
Scott Bentley: Oh, keeping it in the family. Very good.
Jools Walker: So, naturally, Will made Buie Bora’s coffee in an aeropress, and then he put the coffee to his lips.
William Sibling: I find it quite appley, like red apple — it’s pretty sweet as well. It's good. I'm really happy with this coffee.
Jools Walker: If I had said to you, or told you, that it was roasted by a UK specialty roaster, how would you feel about that?
William Sibling: I’m surprised, yeah.
Jools Walker: Will, is it OK if I introduce you to the person who roasted your coffee?
William Sibling: Please do, I'd love that!
Jools Walker: Hi, Will. My name's Jools and I roasted the coffee that you are drinking.
William Sibling: Yes, good job. Do you have any previous experience or advice on how to roast well? Or did you look anything up?
Jools Walker: No. I had no previous experience with that at all.
William Sibling: I think you've done a great job.
Scott Bentley: Well, Jools, maybe you should be roasting the coffee for the next Welsh aeropress championships.
Jools Walker: So, dear listener, if you're in Wales, go and check out Sibling, and we've linked their Instagram in the show notes.
Scott Bentley: Roast coffee, your way with the IKAWA Home.
James Harper: So Scott, Jools, I want to show you what caffeine is actually doing to our bodies, the journey it takes in our systems as soon as we drink it. And to start us off, I want to take us back to that moment that you, Scott, put that coffee to your lips after having been deprived of coffee for so long. Remember this piece?
Scott Bentley: Oh, dreamy!
I remember it well.
James Harper: Now, let me play the entire piece of tape.
Scott Bentley: Oh, dreamy!
James Harper: Scott, you're going for a second gulp there. I said, go for one. I didn't say go for two.
Scott Bentley: That's so cruel. Just a nibble, just a tiny slurp.
James Harper: What's going on there? You automatically reached for a second slurp.
Scott Bentley: A hundred percent. Because it's yum.
James Harper: That thing you just did, going for the second slurp, so this is what was happening as the coffee hits your lips.
Danielle Gulick: So, the first thing it's going to do is find taste receptors, right in your mouth all the way back through your oesophagus, before it's even been metabolized in your stomach. That taste is going to basically turn on your seeking pathway and lead you to want to consume more, because your body has learned that that taste is associated with some really positive feelings.
Scott Bentley: Yeah, it was. I didn’t even think about it.
Jools Walker: Give you another hit.
Scott Bentley: Hit me baby one more time.
James Harper: Right. And here's another interesting thing, even before the coffee has made it all the way into your stomach, a little bit of caffeine is being absorbed immediately.
Lindsy Kass: Caffeine is one of the few substances that can actually be absorbed through the mouth.
James Harper: So maybe you know that — you can actually buy caffeine mouth rinses, which, you know, you can rinse your mouth and get a caffeine buzz. That's what they claim anyway.
Scott Bentley: Wow. Does it give you coffee breath as well?
James Harper: But anyway, the point is the vast majority of the caffeine is being absorbed in our stomach and intestines. And caffeine is going to start having a little bit of an effect around, you know, 30 minutes after drinking. But it actually peaks up until two hours later.
Danielle Gulick: So, this is why most people start drinking first thing when they get up in the morning. Caffeine is actually very slowly absorbed into the bloodstream, and until then it doesn't have any physiologically relevant effects.
Scott Bentley: I always had the impression that it was, like, 20 minutes. I always kind of feel the effects, and when I say effects, you know what I mean…
Jools Walker: Yeah.
Scott Bentley: The bathroom effect.
James Harper: Ah, well, Scott, that could actually be to do with coffee and not caffeine. And Danielle actually mentioned that that's a by-product of the wider coffee drink. Not necessarily caffeine.
Danielle Gulick: But coffee actually acts through something called antidiuretic hormone. And it actually affects your hormone systems in order to alter that need.
James Harper: Anyway, so caffeine. OK, so it ends up in the liver. Here's a little fun fact. Caffeine itself is a relatively complex molecule.
Lindsy Kass: Caffeine is made up of tri methylxanthines. And then, in the liver, those tri methylxanthines get broken down.
James Harper: So we're going to keep calling it caffeine, but it actually gets broken down into a whole number of different things. But just for a bit of a game spell, tri methylxanthines.
Jools Walker: So, tri: T-R-I, what's the other part of the word? I’m trying to break it down now.
Scott Bentley: Methyl: M-Y…
James Harper: You know what, our listeners are going to be really upset by this, at this point.
Scott Bentley: Is this really the spelling bee podcast?
James Harper: But the point is, it's got a Y, it's got an X and it's got a TH in there as well. So anyway, good luck. But Scott, the point is, have you ever considered renaming Caffeine, the magazine, tri methylxanthine?
Scott Bentley: Uh, I don't think I want to commit commercial suicide at this particular point in time.
James Harper: I'm just saying it'd be a more accurate term, surely.
Scott Bentley: Yeah, I'm sure it will.
James Harper: So, anyway, the caffeine is in your blood, and it starts moving across the body, and this is where it begins its magic.
Danielle Gulick: And from there, it's going to travel to two main places. The easy one to understand is the adrenal gland. That's what produces our adrenaline. And so as soon as it starts getting into the adrenal gland and stimulating the release of adrenaline, that's when we're going to start to feel that pick-up in our body. So our heart rate might speed up a little bit. We're going to start to feel like we have maybe a little bit more energy. Our muscles are going to have an easier time contracting.
Jools Walker: Yeah, I co-signed this. Because I remember when we were sitting in the cafe, my heart rate definitely picked up after I drank that coffee.
James Harper: Yeah, Jools, your Apple Watch was reading…
Jools Walker: 102. It's 102. It was 76 BPM five minutes ago.
James Harper: That's the adrenaline being released. It gives us this massive kick, like jolting our bodies into action.
Jools Walker: I guess I can imagine that's actually quite useful, if you want to do a bit better, say, in sporting events.
James Harper: Absolutely. And you know, caffeine has actually been very, very extensively studied in sports. And researchers have found noticeable performance increases. This is what Lindsy Kass told me, the researcher from earlier.
Lindsy Kass: So, it's somewhere between two to four percent. We can't be exact because everybody has a slightly different response to caffeine. Which may not sound a lot, but you only need a one percent change to change your medal position at the Olympics.
Scott Bentley: Yeah, four percent is pretty massive. I mean, when you're talking about illegal doping, I mean, I think I've seen studies in the past that put it around 15 to 20%. But they are completely illegal substances.
James Harper: Yeah. And actually the Olympics has a very interesting history with caffeine. For a long time, it was a banned substance. Would you believe it? Some people actually got disqualified for having too much caffeine in their system. But it appears that caffeine actually affects some parts of the body more than others.
Lonnie Lowery: The effect seems to be greater on the upper body than the lower body.
James Harper: So this is Lonnie Lowery, a senior research scientist at Abbott Nutrition, who had done some academic research on the effects of caffeine before joining Abbott.
Lonnie Lowery: We reliably saw statistically significant improvements in the bench press. Nine to 12% was the range — a typical range.
Jools Walker: How exactly is that working? I mean, is it just the adrenaline rush that's helping these athletes do better?
James Harper: Well, we don't know for certain, and I'm sure the adrenaline definitely helps, but…
Lonnie Lowery: There's a phenomenon called calcium induced calcium release.
Lindsy Kass: Most people don't realize that we have to have calcium to help our muscles contract. And so, it's also been shown that caffeine affects that calcium handling. So, that means that to contract a muscle, you have a threshold, a firing threshold. And when you reach that, like an electrical current, that's when the muscles can contract. And so by changing that, with caffeine, it lowers that threshold.
Jools Walker: OK, I think of calcium and the first thing that I think of is bones. I don't think of muscles.
James Harper: The body has many mysteries.
Jools Walker: This is like being back at secondary school doing GCSE science.
James Harper: So, enough about the body. Let's look at the most interesting aspect of caffeine. What happens when it floats up into our heads and it goes through the brain blood barrier? That's when things really go to town.
Danielle Gulick: The very front of our brain, it's sometimes called the neocortex. It's the part that makes us the most different from other mammals. So, our personality, our ability to have social interactions, a lot of our attention, our working memory. So when you drink your cup of coffee and it gets there, I put you in a scanner and I look at an image, this part of the brain with this high order functioning is lighting up like crazy.
James Harper: So what does that mean in terms of my experience? What am I thinking? Is that changing how I think?
Danielle Gulick: It's not changing how you think, it's changing how well you think. So it's basically increasing your ability to process information. In fact, it's turning on within this area and connected regions, something called the default mode network. But we now know that this is the area that is highly active in goal-directed tasks. So when we're on task, when we're really trying to do something, this particular network lights up, and this is the network that caffeine is lighting up.
James Harper: Is this the reason why programmers joke that they are literally just machines that convert coffee into code?
Danielle Gulick: Essentially, yes. So that caffeine is what allows them to activate with these incredibly detail oriented tasks like coding and allows them to stay on task for a long time and to really focus on multiple details at the same time, that kind of parallel processing.
Scott Bentley: OK, James. So this all sounds fine, but come on, look, how is it that caffeine just enters my life and then all of a sudden I'm on top of the world, I'm above the clouds? The world is a wonderful place.
James Harper: A part of it has to do with, you know, the adrenaline that's rushing through our bodies. But another part of it is down to this really weird quirk of nature, a random fluke, where basically the natural world has created something — caffeine — that has essentially hacked our brains. And specifically, it affects our adenosine receptors.
Danielle Gulick: So, adenosine is a chemical in our brain. It's essentially what you could think of as a sedative. The more it binds to its receptors in our brain, the more it's going to help us relax and disconnect from the things in our environment.
James Harper: So in our brains, there are loads of adenosine receptors and their job is to essentially grab the adenosine that’s floating around. The more they grab, the more tired and drowsy we feel.
Danielle Gulick: It’s basically an off button. So it's a receptor that acts as an off button, it stops signaling. And then when you have caffeine, you are more or less putting a guard over that off button so that nobody can hit it.
James Harper: So if adenosine, when it hits a receptor makes you feel tired, if you put a cover on the receptor, you can't feel tired — because the adenosine can’t hit the button that tells us, “Hey, stop feeling tired.”
Scott Bentley: OK.
Danielle Gulick: So, caffeine is going to come in and it's literally going to block that receptor. It's going to come in, it's going to stick itself in so adenosine hits it and bounces off. So you combine that with the fact that we now have adrenaline rushing through our brain. And so we have a stimulant, the adrenaline rushing through and essentially trying to turn everything on. And then we have caffeine stopping the adenosine pulling us back from that ledge. And so now everything is essentially a go system. And so everything is just go, go, go — high energy and attention.
Scott Bentley: Sounds great.
James Harper: And guess what? It gets even better.
Scott Bentley: Yay!
Danielle Gulick: Caffeine, through actually adenosine receptors again, is able to influence a number of neuro-transmitters, but the big ones are dopamine and glutamine. And so dopamine is the one that we can oftentimes think about as our reward transmitter. This is the one that gets released in response to any kind of drug abuse or anything else that makes us feel good.
It's incremental. So the amount of dopamine you're going to get released in response to, say, heroin is many orders of magnitude greater than what you're going to get in response to caffeine. But it is the same pathway. And so this is why caffeine and coffee can become addictive, because you can become addicted to that little reward boost that you get every time you drink it.
Scott Bentley: Whoa. That got pretty heavy quickly.
Jools Walker: Yeah. But yeah, it's just the word addiction, isn't it.
Scott Bentley: I was more freaking out at the word heroin.
Jools Walker: There is that.
James Harper: Yes, it can be a little bit scary, but, um, I think it's important to put it into perspective. So yes, it can be addictive, but as Danielle mentioned, it's orders of magnitude less than heroin. And because it's so relatively mild, only certain people are going to have a problem with caffeine addiction.
Danielle Gulick: Some people have the genetic makeup to be incredibly sensitive to addiction, meaning that even drugs like caffeine that do not exert a strong effect are likely to become addictive for them. And so for people who perhaps have tried a cigarette and found that they couldn't stop after that, or who find that when they go out drinking with their friends, they are the one that never quite manages to stop before the downside kicks in, coffee is probably going to have similar issues.
Scott Bentley: So it's not that the substance itself is particularly bad, but it's more about the person and if they are that type that gets addicted very quickly.
Jools Walker: What, so like addictive personalities?
James Harper: Yeah.
Jools Walker: Oh.
James Harper: And if you are that person, be careful. And the other thing we really should consider is that…
Danielle Gulick: Caffeine is in natural products. We even get small amounts of caffeine in chocolate, so it's not some synthetic drug of abuse that has high addictive potential. There's a risk in a small group, but for a lot of people, it's simply giving you that boost that your brain could get from lots of other things. If you went out, if you were so motivated and ran five miles first thing in the morning, you would get a similar boost in your energy. So caffeine is just perhaps a more expedient approach to getting that boost.
James Harper: I would personally prefer to drink a cup of coffee rather than run five miles.
But anyway, the party that caffeine is making in our heads doesn’t stop there. Because in addition to that little dopamine kick that you’re going to get…
Danielle Gulick: It also is active in the glutamine circuit, and can affect serotonin release. And these are more related to our mood. And so this is why caffeine has actually been purported to possibly be an antidepressant. So coffee drinking can reduce symptoms of depression in a lot of patients. And that's because it can, by blocking adenosine receptors, allow the release of glutamine into the serotonergic system. And remember, our antidepressants are largely serotonin drugs.
James Harper: So, peeps, let's just freeze frame here. Right? You had your coffee about four hours ago, and now you're at the peak, right? You got a trend lens, sparking everything to life. All those pesky adenosines are being kept away. So you're not feeling tired at all. You've got this teeny tiny high from the dopamine and you're feeling this really happy feel-good molecule serotonin kind of bouncing around. You're crushing all your tasks. Life is great. You're on top of the world and… the crash.
Scott Bentley: What goes up must come down.
James Harper: And what's interesting is that this great unwinding from our caffeine high actually comes back down to those adenosine receptors. Because the thing is this, right…
Danielle Gulick: The problem is that adenosine keeps building up. Nothing we do is going to stop that build up.
Scott Bentley: So James, if I read this correctly, there's this basically soup of adenosine just sitting there waiting, filling up our brains, and it's just got nowhere to go. Nothing to jump onto.
James Harper: Right.
Danielle Gulick: And so, the longer caffeine is there, the more it builds up, and this is why you essentially come down from your caffeine high. You've got all that energy. You're going, going. The caffeine gets metabolized. You don't just get a little sleepy, you crash.
Scott Bentley: Just waiting in the wings.
Jools Walker: It's just sitting there patiently. I'm now slightly confused. Because I need to know why we were feeling so bad when we didn't drink caffeine for 24 hours.
James Harper: The thing is, when you drink coffee on a regular basis, the caffeine is there blocking adenosine receptors. That's what it does. And it does so with regularity, every morning. You know, “Morning, I'm going to sit on this receptor now, thanks.” And the thing is right. The brain compensates by creating more adenosine receptors,
Scott Bentley: So what you're saying is the more caffeine you drink, the more your brain is trying to compensate for that by building these adenosine receptors. So when you do come off of the coffee or the caffeine, there are so many more receptors that get filled up so quickly.
James Harper: Exactly. Imagine you're a piece of adenosine floating around. It's like, “oh, there’s a receptor,” immediately. Whereas if you hadn't drunk coffee on a regular basis, you know, it takes you maybe a bit longer to find that receptor, but now there are so many receptors, when they're not blocked with caffeine, it's really quick..
Scott Bentley: I see. I see. That makes so much sense.
Jools Walker: That's why everything felt really subdued and mellow when we got off caffeine for 24 hours.
James Harper: Mmm, we were just floating, drowning in adenosine hitting our receptors.
Jools Walker: It's just too much.
James Harper: Now here's an interesting thing. If we pushed that 24 hour no caffeine to a week, this is what would start to happen to us.
Danielle Gulick: We do have withdrawal symptoms. One of the biggest is going to be, oftentimes, some anxiety that's going to come in. That can come in from the inability of the brain to process the rapid shift in caffeine and that mood effect that it was having. So we can have a drop there.
James Harper: Remember me? I mean, I honestly felt like I just didn't care about the world at one point
Scott Bentley: OK. So that's the mood thing, but what was the headache?
James Harper: That's a completely different mechanism. Because the thing is, Caffeine also affects our blood vessels.
Danielle Gulick: So caffeine also acts normally as a vasoconstrictor. It tightens our blood vessels. And this is why caffeine is great for headaches. Headaches tend to come from blood pounding through your blood vessels. And so, what caffeine does is it constricts those vessels. It reduces the amount of blood flow through them. And so it actually reduces headaches. This is why it's a proven treatment for migraines.
Scott Bentley: But James, why did I have a headache, then, when I didn’t have caffeine? Surely that's the opposite.
James Harper: Right.
Danielle Gulick: Well, the problem is, when the caffeine goes away, all of that nice vasoconstriction disappears. The blood vessels are essentially going to dilate — they're going to get much bigger. You're going to have tumultuous blood flow. And so, oftentimes, people will have very bad headaches as well.
James Harper: Basically, your body and brain has kind of optimized the size of the blood vessels, because they anticipate you having caffeine on a regular basis.
Scott Bentley: So, if this is correct, when I stopped drinking caffeine, the blood vessels in my head increased in size and started throbbing.
James Harper: Absolutely. And that is the headache.
Jools Walker: Your brain has been conditioned to caffeine intake. But how long does it then take for your brain to readjust to not having caffeine? How long would that pain last?
James Harper: Brace yourselves.
Danielle Gulick: So the adenosine receptors can get back to a new normal within a week or two. So basically the neurons just eat the receptors, the extra ones, they just get pulled back into the cell and the components get broken down. So that's not a super long process.
Jools Walker: I'm imagining it like Pac-Man coming along and eating the receptors.
James Harper: So as far as not feeling tired, that will go away within about a week, let's say. However…
Danielle Gulick: But the wiring can take months. And this is why people have a lot of trouble when they try to stop drinking. One to two weeks are the most miserable, because that's when the receptors are still heightened.
But even after a couple of weeks, a lot of people report that they're still having trouble with attention, for example. Because the brain had rewired those higher order areas in order to be responsive to caffeine. And until it can fix it, until it can rewire, you are not going to get your normal ability to pay attention and to process.
James Harper: So that could be months before the brain totally rewires to not be used to caffeine being in the system anymore.
Scott Bentley: Just keep drinking coffee, peeps.
Jools Walker: It keeps you happy. Coffee makes you happy.
James Harper: Maybe some listeners might be thinking to themselves: Damn, what have I done to myself? I got myself addicted to this thing.
Jools Walker: It’s the A-word.
Scott Bentley: But guys, at the end of the day, coffee brings me joy. I mean, I think it brings me more positives than it does negatives. I'm down with having something that brings me more joy than it does without it.
Jools Walker: Other than the joy element, and that's something that I can relate to as well, there are the health sides to coffee as well. So obviously, our previous episode that we did, “Is My Coffee Killing Me?” — and there will be a link in the show notes for that as well. We went on a journey and actually ended up learning that coffee has a number of great positive health effects too.
James Harper: Peeps, both great points. But caffeine itself, just the drug caffeine, also has positive health effects.
Danielle Gulick: The final effect that we haven't talked about is that caffeine is actually neuroprotective, meaning it actually protects neurons in aging and in aging related diseases. So it's been shown to actually help patients with Alzheimer's disease. It reduces the breakdowns in their brain. It does the same in normal aging. And to some degree it can even boost memory, not just attention, but the actual storage and maintenance of memories. So it does that because once again, those terrible adenosine receptors, they become pathological as you get older and they can actually drive the disease processes that lead neurons to break down and die. And so chronic caffeine, yes we can habituate there are some downsides, but it actually has this big upside of protecting the brain long-term.
Scott Bentley: Yay, coffee!
Jools Walker: This is genuinely fascinating that it's not ending on a downer as to what caffeine can do to you.
Scott Bentley: And I think this also speaks to something else. And I know we've had a conversation about this in a previous episode, but this whole idea of clean eating and like, by doing this thing you can wipe out all bad things in your life is just buncombe. Everything you take will have some positives and some negatives on your life and your health and everything about it. It's finding those things which have more positive impacts and less negative. There's no way you're ever going to be able to find anything that is only doing positive things. That's just not how the world is made.
James Harper: So there you have it, peeps. That's the journey that takes place in your body and brain every time you take a sip of coffee in the morning.
Jools Walker: OK, so I think it's now time for those credits.
James Harper: Now, dear listener, if you want to support the show, one great way to do it is on Patreon. It helps keep our lights on, because, frankly, about 100 hours of work goes into every episode.
Scott Bentley: And if you're not able to support us there, then you can do so for free by telling your friends about the show. The more people who listen, the easier it is for us to keep going.
Jools Walker: Now one good way to tell your friends about the show is to hop on Instagram and create an Instagram story from a screen grab of your podcast player. And you can tag us. That's me, @ladyvelo; Scott, @caffeinemagazine; and James, @Filterstoriespodcast. And guess what? We'll repost it.
James Harper: Guaranteed. Now this podcast was produced by myself, and I also wrote and played the piano music, and our editor is Amedeo Berta.
Jools Walker: And we need to give a huge thank you to all of the very clever people who gave us their time for this episode. So thank you, Danielle Gulick Jonathan Morris, Lindsy Kass and Lonnie Lowery.
Scott Bentley: Yes, and, dear listener, we'll be renaming the show going forward to the bothering clever people podcast.
James Harper: And you can go deeper into their work because we've linked their social media handles in the show notes, and Jonathan's excellent book: Coffee: A Global History.
Jools Walker: Now, Scott, what are we going to be exploring in our next episode?
Scott Bentley: Well, I'll be honest with you, Jools. After witnessing your triumphs in roasting, I was feeling a little, a little left behind. I was a bit jel.
Jools Walker: Well jel.
Scott Bentley: Yeah. So I decided to delve into the weeds on this and have my own roasting adventure.
James Harper: But until then, dear listener, listen, enjoy your coffee. And we'll see you next time on Adventures in Tri Methylxanthines.