Science Vs - Caffeine: How Much is Too Much?

Episode Date: November 30, 2023

Caffeine is a drug that tons of us take every day. But is that a bad thing? And if we get it in the form of energy drinks, is that super dangerous? We talk to Dr. Astrid Nehlig, Prof. Gregory Marcus, and Prof. Sachin Shah.  Find our transcript here: https://bit.ly/ScienceVsCaffeineEnergyDrinks In this episode, we cover: (00:00) Chapter 1: We love/hate caffeine (02:12) Chapter 2: Coffee and our guts (07:12) Chapter 3: Coffee and our brains (12:40) Chapter 4: Coffee and our zzzzzzs (17:42) Chapter 5: Coffee makes us go vroom vroom vroom! (20:30) Chapter 6: Are we caffeine addicts?  (28:04) Chapter 7: Are energy drinks dangerous? This episode was produced by Rose Rimler, with help from Wendy Zukerman, as well as Nick DelRose, Joel Werner, and Michelle Dang. We’re edited by Blythe Terrell. Fact checking by Sarah Baum. Mix and sound design by Bumi Hidaka. Music written by Bobby Lord, Bumi Hidaka, Emma Munger and Peter Leonard. Special thanks to all the researchers we spoke to for this episode – including Dr. Bryan Saunders, Dr. Sergi Ferré, Prof. Andreas Heinz, Prof. Christine Curran, Dr. Erikka Loftfield, Dr. Felix Oberhoffer, Dr. Alan Wayne Jones, and Dr. Vijay Yadav. Extra special thanks to Jason Vytlacil and the Zukerman family. Science Vs is a Spotify Studios Original. Listen for free on Spotify or wherever you get your podcasts. We are everywhere that podcasts are! If you are listening on Spotify, follow us and tap the bell for episode notifications. And if you like us, give a five star review!  Learn more about your ad choices. Visit podcastchoices.com/adchoices

Hi, I'm Wendy Zuckerman and you're listening to Science Versus, and this is the show that pits facts against flat whites. On today's show, caffeine, should you quit it? Caffeine is one of the most used drugs in the world. 85% of people in the US drink at least one caffeinated beverage each day, and that includes kids. But yet, despite the fact that we are shoving this drink down our pie holes, there have always been these fears that caffeine is bad for our health.

Your cup of coffee could soon come with a spoonful of cancer warning. My heart was racing. I was super anxious. Something was happening. I was having a panic attack. Could it all be a sign, though, of a serious problem? A problem like caffeine addiction? And our worries around caffeine have reached new heights when it comes to energy drinks. Just this year, US lawmakers, like Senator Chuck Schumer, were fussing over this new energy drink called Prime.

The product has so much caffeine in it that it puts Red Bull to shame. One family sued Panera after their daughter, who had a heart condition, died when she drank their caffeinated lemonade. And this is the latest in a long line of scary stories of people, often younger people, dying soon after drinking energy drinks. Davis collapsed in the classroom of his high school in South Carolina. It wasn't a car crash that took his life. Instead, it was an energy drinks. Davis collapsed in the classroom of his high school in South Carolina. It wasn't a car crash that took his life. Instead, it was an energy drink. She drank two 24-ounce energy drinks in less than 24 hours. And it took her life. So today on the show,

what is this drug doing to our brains and our bodies? Is it ruining our sleep, turning us into caffeine addicts, and potentially even killing us? When it comes to caffeine, there's a lot of, my heart was racing, but then there's science. Science versus caffeine is coming up just after the break. It's season three of The Joy of Why, and I still have a lot of questions. Like, what is this thing we call time? Why does altruism exist? And where is Jan 11? I'm here, astrophysicist and co-host, ready for anything.

That's right. I'm bringing in the A-team. So brace yourselves. Get ready to learn. I'm Jan 11. I'm bringing in the A-team. So brace yourselves. Get ready to learn. I'm Jana Levin. I'm Steve Strogatz. And this is... Quantum Magazine's podcast, The Joy of Why.

New episodes drop every other Thursday, starting February 1st. What does the AI revolution mean for jobs, for getting things done? Who are the people creating this technology? And what do they think? I'm Rana El-Khelyoubi, an AI scientist, entrepreneur, investor, and now host of the new podcast, Pioneers of AI. Think of it as your guide for all things AI, with the most human issues at the center. Join me every Wednesday for Pioneers of AI. And don't forget to subscribe wherever you tune in.

Welcome back. Today on the show, we are taking on caffeine and energy drinks to find out once and for all how bad is this stuff? What is it doing to our bodies and brains? To tell us all about it is senior producer Rose Rimler. Hey, Rose. Hi, Wendy. So over the summer in the U.S., there was a lot of hubbub about this energy drink prime.

I guess this was a bit of your inspiration for wanting to tackle this episode. Yeah. A lot of the talk was about how it's got a crazy amount of caffeine. It's bad for us. And energy drinks are bad for us. And sort of just this feeling that like caffeine is bad for us. And I don't know about you, but I have caffeine every day when I have my coffee. So it made me wonder, like, is my caffeine habit something I should take a second look at? Or is caffeine like just all hunky-dory? Yes. I love this question because caffeine has been a thing that I have actively said, you know what? I'm not into meth, but I'm going to be fine with my caffeine use. You know,

I felt guilty about it and I do want to know whether I need to. So where do we begin? Let's start with Astrid Nielig. She's a caffeine researcher. And she says she hears this idea about people feeling guilty about their caffeine intake all the time. I meet somebody and they ask me on what I work. And I say, oh, I work on coffees. And people are very shy all of a sudden and withdrawing a bit and telling me, oh, it's very bad. I should probably not drink. Astrid is an emeritus research director at

France's National Institute of Health and Medical Research, and she has studied caffeine for decades. So with her help, I'm going to walk you through what caffeine is doing to your brain and your body. Okay. So Wendy, I asked you to come prepared with your favorite caffeinated beverage. So what did you bring today? I have an oat cappuccino. Okay. Take a sip. Should I do it like ASMR or if I'm, I guess if you have misophonia, just chewed out. Okay, so I'm going to tell you what it's doing right now. Okay. So scientists think that once the coffee gets to your stomach, it's basically going to wake up your guts.

It's going to get your stomach to make more acid. It's going to get your liver to start making bile. So it's really an activator of digestion. Is that why, not to be crude, but sometimes you have to go number two after you drink coffee? Yeah. At least in some especially sensitive individuals, yeah, it's like that. We know this because, thankfully, some scientists in the 80s got permission to stick probes up people's buttholes. Oh. And then give them coffee to see what happens. And the reason they wanted to test it this way is because they had given

these people a survey and said, does do any beverages make you have to poop? And a third of the people in this 100-person survey said, yeah, actually coffee makes me have to poop. So they got some of these people and some other non-responders into the lab and they put this probe up in their upper part of their rectum. And so what they were looking for was to see, is there an actual physical change in your lower intestine when you've had coffee? And what did they find? In the people who said, yes, coffee does this to me, they could actually measure increased rectal activity.

Oh, I'm clenching. I'm clenching. Have you been clenching as you've been reading this research? No, I'm quite relaxed. Oh, okay. As soon as you said increased rectal activity, I was just like. Well, I like kind of,

I like thinking about like these sort of peristalsis of your butthole, you know, like how food gets down. It's something else has to, to make it come up, come out. And that increased. Right. In response to coffee for some people. Interesting. Okay. I have a very important question. Yeah. How quickly, how quickly does this activation happen? Because... It can happen within minutes. Oh my God, I feel so validated. Wow.

Because I, like, I will sometimes just take a few sips of coffee and just like need to do a shit. Sorry for the kids out there. Need to do a big crap. And I have come to believe that, oh, it's just placebo at this point. Like surely it can't be working that quickly, but it can. It can. Like just so you know, Rose, because this is my first coffee for the day.

Yeah, if you have to run off on the way. No, I don't. Because I took a couple of sips before our chat and I'm all sorted. Took care of business. I appreciate that level of planning. Always come prepared. That is me. Okay. So that's how coffee can affect the gut. And from there, caffeine starts getting absorbed in your bloodstream. Okay.

It depends on your body, but this takes about half an hour to an hour to peak. So caffeine's in your blood, it gets to the blood-brain barrier, and it just sails right past it. I talked to Astrid about this. When I think of coffee entering our brain, I just imagine my brain is a sponge that just soaks up the coffee.

Is that kind of right? Yeah, why not? Yes, because, you know, you drink your coffee and all of a sudden, your whole body, including your brain, gets invaded by these caffeine molecules. In the brain, it stimulates some neurotransmitters, including dopamine. And that gives us a bit of a mood boost. But the big thing that caffeine does in our brain is, of course, that it wakes you up. Yes.

Yes. It's claimed to fame. And this happens because caffeine basically barges into the brain and like elbows out this molecule called adenosine from these special receptors. And what adenosine is, it's like the sleepy molecule. So it like binds receptors in your brain that basically turn on the feeling of sleepiness. So caffeine's like out of my way. I'm coming in.

I'm going to buy into those adenosine receptors. And that means you don't feel as sleepy. So just to get like real nerdy here, it's not that caffeine is binding onto these receptors and going, let's go, brain get excited. It's rather the lack of adenosine, the lack of sleepiness that wakes you up. Yeah, and that's what we like about caffeine, right?

Like that is the whole point that it wakes us up. And it's not just about being awake. We actually have a lot of evidence that caffeine helps us be more alert, more focused, and helps us to react to stuff faster. This has been quite extensively studied. This is clear. So if I take a stupid example, but you are facing a lion. If you have been drinking caffeine, you will react faster and you will run away before. Could save your life.

Yeah, absolutely. Could make a difference and save your life. And scientists have actually tested this. They gave free coffee to people who were visiting the zoo that day. And then they opened the lion cage. Amazing. And they got away? They got away? Some got away, some didn't. That's right. Those in the placebo group were less likely to get away.

We are joking. No, there are no lions. But there is one small study that suggests that caffeine really could save your life. So this study, researchers had people stay up really late and then drive a car on the highway in the middle of the night. This is a real car on a real highway. Oh my God. They had a driving instructor in the next seat who could take over control if things were getting bad.

My goodness. So the scientists were counting how many times people veered out of their lane when they had placebo versus when they had coffee. And it turns out the coffee made a big difference. The number of times people veered over the lane went way down after people had coffee. Okay. The powers of caffeine. Yes, right.

And then I found this study that just made me laugh because it's just such a funny concept. The scientists really wanted to find out if coffee can make us appreciate humor more. When we are sleep deprived, we kind of lose our sense of humor or it takes a hit. So the researchers were wondering, would caffeine give us back our sense of humor or improve that? Uh-huh. And I don't know if you know this, Wendy, but there is a scientific test of sense of humor. Oh my gosh, that was entirely my next question. What is the joke that scientists ask

that they're like, if you find this funny, you have a good sense of humor? Then you're operating on full cylinders. Yes. Yeah, so they would show them like two different pictures and ask which picture is funnier or more podcast appropriate. They would have them read two different pictures and ask which picture is funnier or more podcast appropriate.

They would have them read two different headlines, fake news headlines, and ask which is funnier. So here's an example. I'm curious if you're going to get it right. I feel very cocky about my sense of humor. Okay. So here's the example. Which of these two headlines is funnier? Veterinarian investigates failed panda mating.

That's headline one. Or panda mating fails, veterinarian takes over. That's headline two. Which is funnier? Headline two is funnier because it suggests. I mean, headline one isn't funny at all, right? But headline two suggests. Just something really, really disturbing, actually.

And the third headline is veterinarinary and f***ed panda. You're right, it is the second headline. Yes. According to science, that is objectively funnier, which I guess it is. Also, I'm so proud of them for being a little bit naughty. Well, it turns out that the caffeine in this case did not help people. Yeah, I totally forgot we were talking about caffeine. So bottom line, caffeine may not improve your humor,

but we have lots of evidence to show that it's not a myth or a placebo effect. Like caffeine does help us wake up, stay up, stay alert. So that brings us to something that people actually worry about with caffeine, that it's keeping you too awake, that it's messing with your sleep. Yes, I have worried about this too. And in fact, cut down on caffeine because I've been worried about this. So let's meet Gregory Marcus. I'm just going to move my dog. Come on. He's a cardiologist and a professor of medicine at UCSF.

If you could be any caffeinated product, which caffeinated product would you be? Oh, cappuccino, no doubt. I guess he sees himself as serious on the bottom, but like a little bit frothy and sweet on the top. You know, he didn't refer to himself that way, but based on my conversation with Greg, I would say that's an accurate description of him.

Buttercup has been removed for the moment. So Greg did this like pretty unique study where he got people to either drink coffee or not drink coffee at random. And then he was able to like precisely measure exactly how that affected their sleep. Ooh, okay. So they recruited about 100 coffee drinkers in San Francisco. They put a bunch of stuff on them. They wore a Fitbit, which measured how well they slept and their steps. And they wore a portable heart monitor. So it's essentially like a very big band-aid,

and it goes on the chest to the left of the sternum, essentially. And like, interestingly, in the middle of the sticker, there's this big button. We instructed them, just push that button whenever you have a cup of coffee or a caffeinated drink. So you have your coffee, and you hit your button. And one way they made sure that people were doing what they were supposed to do, you know, not drinking coffee if they weren't supposed to that day, they had everyone in the study get this app on their phone that allowed the team to monitor their location. So the team could see if they visited coffee shops. So if they went to a coffee shop on a day they weren't supposed to have caffeine, that would be highly suspicious.

Would there be like a button goes off in your office, like a flashing red light? Would they get an electric shock? Yeah, that's a good idea. Interesting idea. That's exactly what I was thinking. Well, luckily for the people in the study, we didn't design it. They did not get shocked. Oh, okay. Okay. So I'm going to go out of the

lib heroes and say that on average, coffee did affect people's sleep. Yes. But the key question here is how much? Because there is this idea that coffee just really robs you of your sleep. Well, in reality, Greg found... On days where people were randomly assigned to consume coffee, that evening, they on average slept 30 minutes less. Damn! Yeah, so on average, if they were in the coffee drinking group, they had half an hour less sleep. And Greg could even dive into the research and figure out how much sleep each cup of coffee costs these people. And it turns out about 15 minutes of sleep. Okay, so loosely for every shot of espresso or just like regular coffee, you'll get around 15 minutes less sleep a day.

Uh-huh. Okay. That's not terrible. That's not... Oh, oh, oh. But... There is an important caveat, which is that Greg found this really varied from person to person

based on their genetics. So on top of all that other stuff, Greg also took saliva samples from people and worked out if they had these genes that make them either a fast or a slow metabolizer of caffeine. And he found that the slow metabolizers lost closer to an hour of sleep a night on average. Oh, wow. And the fast metabolizers lost basically no sleep at all. Huh.

So people who say, oh, yeah, I can have a, you know, cup of coffee at night, I go right to sleep. They may be really telling the truth. My mom proudly says that she could drink coffee like at dinner time and it will not affect her sleep

to the point where she will mock me when she wants a coffee at 4 p.m. and I say, too late for me. Mama Zook vindicated once more by a

Science vs. Episode. Well, it's like you're me, Mama Zook vindicated once more by a Science Versus episode. Well, it's like you're both right. She's right that she can have a coffee late at night. And you're right that you can't. You're probably both right. Okay. But you know who isn't right? Is those people online, influencers, I don't know what we want to call them. Anyway, who have these like definitive statements about how much coffee you're allowed to drink and you need to stop at 10 a.m. And you can only drink two cups or whatever that they're saying. Like actually what the science says is this is very dependent on your genetics. And those blanket statements are kind of bollocks.

Yeah. Okay. So that's sleep. But Greg's study looked at something else that people don't necessarily associate with having a cup of coffee. And that is exercise. So on top of measuring sleep,

he also measured how many steps they took every day. And. On days randomly assigned to coffee, participants on average exhibited a thousand more steps on those days. Wow, that's a lot. It is a lot. And in fact, there's other evidence that that magnitude of a difference may be meaningful in the long run in enhancing longevity.

Oh, wow. Yeah. For example, one study found that older women who take 5,000 steps a day live longer than similar women who took 4,000 steps a day. Oh, that's cool. And it's not just step count. We actually have a lot of data showing that caffeine can help us athletically. So when people have caffeine before they exercise, they tend to go a little

harder. So like people will be able to run for longer or, for example, do more squats. There's a study that looked at swimmers doing a 1500 meter race. So that's almost a mile. And it found that having some caffeine beforehand shaved 23 seconds off their time compared to a placebo. And having caffeine before exercise is considered safe as long as you don't overdo it. Like the equivalent of one or two coffees before exercising. Wow. And so why is that happening? Well, you know how caffeine can boost your dopamine.

So that might be like putting us in a better mood so we can work harder. And we also know that caffeine can kind of turn the dial down on feelings of pain. That's why some painkillers have caffeine in them. So maybe athletes aren't feeling the burn quite as much. And then finally, there's some evidence that caffeine can actually increase the amount of calcium getting released by your cells, which could make your muscles work better. Wow. So, do you still feel guilty about your coffee? Oh, no. Thus far, no. But at the same time, we haven't really talked about risks yet.

Good point. So next we're going to talk about is caffeine addictive? And what's going on with the scary stories we hear about people dying after drinking energy drinks? And that's coming up just after this quick coffee break. Coffee break? Welcome back. Today on the show, we are asking, should you quit your caffeine? Should you just spit out your coffee, spill your tea on the floor, say goodbye to your energy drinks.

Rose Rimler, senior producer at Science Versus, is telling us all about it. Hey, Rose. Hey, Wendy. So the next thing I want to dive into is this idea that you can get addicted to caffeine. Mm-hmm. You know, and I think a lot of that comes from this, like, terrible withdrawal that some people have when they stop it. Now, caffeine withdrawal is a real thing.

And people who quit coffee all of a sudden can totally feel sick. Like about half of them will get a headache. This could be because caffeine restricts blood flow to the brain. And when we go off it, the blood whooshes back in. Oh, wow. Some people even feel like they have the flu and they feel like really tired and crappy. So send them help. So pray for them. Do I need to pray for them? Do I? Like if they, if suddenly there was an apocalypse and they couldn't get their coffee, how bad would it be?

All those symptoms, they go away for most people somewhere between two to nine days. Okay. So if they can survive for nine days, they'll be back to normal. Yes. Just hunker down in your bunker. Hunker in your bunker. Great. And it'll play itself out.

Right, okay. But back to this addiction thing. So, you know, you might reasonably call yourself dependent on caffeine if you feel sick without it. But that's not the same thing as addiction. With addiction, what experts point to is that you are using a substance even though it's bad for you. It has negative consequences on your life.

Maybe you even like really want to quit and you can't. And I think right now, the general idea among scientists is that this is not a problem for most people. They don't really see any evidence of this like negatively affecting people. Right, for most people. And then what about tolerance? Like this idea that you need to have more and more caffeine to have the same effect. Yeah, we typically don't really see that with caffeine.

And one reason is probably that at a high dose, caffeine starts to activate this other type of adenosine receptor in our brain that causes anxiety. Oh, this is why you get all jittery and like, oh, if you have too much caffeine. There's sort of a threshold you can cross from all the feeling like alert and energetic and kind of good to, oh, now I feel anxious and jittery and weird. And one researcher I spoke to said that for caffeine specifically, this window, he calls it a window between the good and the bad feelings, is pretty short. So you can kind of easily tip yourself over when you've had more caffeine into that anxious feeling.

And if you're starting to feel that way, you know, many people would probably put down their third venti frappuccino of the day at that point. So there's kind of a natural cap for most people on how much caffeine we're going to drink every day. Yeah. Yeah, yeah, yeah. You know, because recently I did, I guess we're in the middle of the season. It's a hard place to be. And I was, I did start drinking.

I was like, fuck it, I'm just going to drink more coffee. And it did make me feel anxious. And so I was like, no, no, no, just go back to one or two cups. Like just, yeah, this isn't, go for a run instead or whatever. Yeah, it's not like worth it to most people. Yeah. At a certain point. And you know, this can be different if you're mixing caffeine with other drugs.

That's more dangerous. But bottom line, caffeine is not considered a drug of abuse. There is no caffeine use disorder in the DSM, you know, the big manual for psychiatric disorders. It's been proposed, but right now it's not officially in there. Okay, so for now we could say science says caffeine isn't really that addictive. Is that where we're at? I think so.

I think, yeah. Yeah, I think so. So thus far, all right, it doesn't, it's really not seeming like caffeine is that bad. And I'm trying to think why I thought caffeine was bad for you. I actually might have an answer. In the 90s, there was news that coffee was associated with bladder cancer. Oh, really? But that has been debunked in more recent years.

Turns out it was not a real association. But even if you don't remember that stuff about bladder cancer, I think that sort of percolated, so to speak, in the culture. And we haven't quite gotten over it. Plus, there's a lot of fears around pregnancy and caffeine. And that is something to think about because we know that caffeine can cross the placenta and get to the fetus. And so drinking a lot of caffeine when you're pregnant isn't recommended. But, you know, health guidelines from around the world, they say you can have one or two cups of coffee a day if you're pregnant. Right. You know, overall, just putting aside pregnancy, I walked away feeling pretty reassured about caffeine

because here's something that I thought was like really kind of great. So it turns out that people who drink coffee have a lower risk of Parkinson's disease, depression, type 2 diabetes, and heart disease. Really? And although we once thought coffee was carcinogenic, more recent studies have found that it actually might reduce your risk of some cancers. What? Like liver and breast cancer. Are you kidding me?

Are you serious? Like, yeah. And even drinking coffee is associated with being less likely to die earlier. So the biggest benefits are seen in people who drink two to three cups a day. But even at higher amounts, we still have people apparently getting some benefit. Like one study looked at people drinking as much as eight cups of coffee a day and found they still lived a little longer than people who didn't drink any coffee. Wow. Yeah. I mean, there aren't that many people that

drink eight cups of coffee a day. So that's kind of a smaller sample size. But I think that point stands that the science suggests that coffee is not actively harming you. And caffeinated tea also seems to be good for us. I mean, are we sure? Are we sure about this? Like, why would caffeine, why would coffee and tea have these benefits? Nobody totally knows. It could have something to do with the exercise boosts you get from caffeine, because like we said earlier, like walking more steps a day. But also, it could be that it's not really about the caffeine. It's about the other stuff that's in the plant. So the coffee bean, the tea leaf. There's a lot of stuff in there that's really good for us and is anti-inflammatory and has antioxidant potential.

Wow. I'm feeling very good about my coffees. I was not expecting this from science, but thank you. Anytime. So then, I don't want to crap all over this party. Is that how that phrase goes? Yes. Rain on your parade? Yes, yes.

Is that what I mean? It's a very, it's a visceral expression. You see, I don't know if I have a good sense of humor. I just laugh so much at my own jokes. I know a test you can take. Great. Okay, but what does this all mean about the energy drinks issue? Because to change the tune tune to get quite serious like that

there are these stories about energy drinks killing people so what is what does this mean which is the opposite of what i just told you about coffee right yeah well a lot of times what people say is the problem is that energy drinks are dangerous because they are packed way too full of caffeine. Right. Right. But the funny thing is when you look at the labels, many of them really don't have that much caffeine in them. Oh, how much caffeine is in your average energy drink? Well, okay. So like this summer, Chuck Schumer said that Prime Energy had an eye-popping amount of caffeine. So I looked up the label of Prime. It contains 200 milligrams of caffeine. What? 200? What, like two shots of espresso? That's it? That's it?

Yeah, two or three, depending on how you make them. I love that you were like, so I went deep undercover. I bought a Prime and I turned it around and I looked at the label. And of course you can overdose on caffeine. The toxic effects are thought to start at 1200 milligrams, which is about six cans of Prime. And there are case reports of people drinking a bunch of energy drinks and being hospitalized. But here's where things get mysterious. There are reports of people, often younger people, dying after drinking less than that, which suggests this isn't just about caffeine.

And Professor Sachin Shah saw reports like that in the news and thought, Hey, there's something going on here. You know, it was actually a little bit sad at points talking to Sachin because he's actually been in touch with the parents of kids who have died after drinking energy drinks. You know, we've had emails from other countries, one where somebody's like, I have kept the drink that my kid drank from the time when they drank it, just in case it helps future scientists. I'm happy to give you that drink.

Oh, that's heartbreaking. Yes. So Sachin, who's a professor of pharmacy at the University of the Pacific in California, he wanted to know why would anyone die after drinking a couple of energy drinks? Yeah, yeah. So to get to the bottom of it, he did this study where he got people to drink a couple of energy drinks and then looked at what their heart was doing. Because typically what we see in these cases is that someone's heart stops beating shortly after drinking energy drinks. So he got these volunteers to come into the lab. He hooked them up to an EKG. Many people see this on TV shows

when they have somebody in the hospital, they're connected to this screen, they're lying in the hospital, and they show this squiggly line. Yes, yes. That's looking at your heart rhythm. Beep, beep, beep. Yes.

Just to avoid us putting the sound effect in. Always thinking ahead. Okay, so they've drunk the energy drinks. And then he monitored them. And one hour, two hours, four hours, six hours, and 24 hours. And he was looking at this particular part of our heart's rhythm that's called the QT interval, which is basically looking at how long it takes your ventricles

to contract after every beat. And if this takes longer than normal, it can throw your heart into something that's called fibrillation, which is like, instead of going squeeze, squeeze, squeeze, your heart starts quivering like a nervous chihuahua. And the problem with that is that your heart isn't actually pumping out any blood and you can die. Oh, man. Okay, so did the energy drinks muck up the QT interval? So, yeah.

So, you know, what was interesting is in that first study, we found that energy drinks were prolonging the QT interval by 10 milliseconds. A follow-up study he did found this again, that the energy drinks extended the QT interval by this time, six milliseconds. And Sachin points out that several drugs have been pulled from the market for prolonging the QT interval by six milliseconds. Wow. Okay. So if I were to drink the equivalent caffeine from what he gave them, but in coffee, would my QT interval be extended like that? No. Studies have also looked at this for caffeine or for coffee, and they don't find the same thing. And actually, in Sachin's study, in one of his studies, they included a caffeinated control, and it didn't do the same thing to people's hearts. So if energy drinks are doing this, why aren't heaps of people like getting heart attacks and dying after drinking energy drinks? I mean, millions of people must be guzzling this stuff

and only a handful have died or so. Yeah. I mean, it's not like anyone in Sachin's study had to be rushed to the hospital. Right, right. But the thinking here is that there are some people who could be really vulnerable to this. Like people who have heartbeats that already have kind of a long QT interval. And then the energy drink might extend it even more. And that could tip you over into Chihuahua territory. Right, right.

One study actually found this. It gave energy drinks to people with a heart condition like that and found that the drinks extended their QT interval in such a way it was actually dangerous. And it's worth pointing out that the woman who died after drinking caffeinated lemonade at Panera, reportedly she had a heart condition like this. And we did reach out to Panera for comment, but they didn't respond.

Uh-huh. So then can we go back to that point? Like if it wasn't the caffeine, if it's not the caffeine doing this, then what is it in energy drinks that's causing this? Yeah. I mean, in Sachin's study, they tested a couple different brands. They both had caffeine, taurine, which is an amino acid, and a supplement called glucuronolactone, which is found in a lot of energy drinks, like Red Bull. So this is the ingredients. This is how we get wings.

Is that right? This is the wing recipe. Yes. Okay. So all this stuff together seemed to extend the QT interval. But then I found this one study that tried to really get to the bottom of which ingredient is the bad guy here. So they basically deconstructed a Red Bull and had people drink a few of the components one at a time while they were hooked up to an EKG, just like Satchin. And after drinking the Red Bull,

volunteers had a prolonged QT interval, but none of the individual components did this. What? Neither did the combination of caffeine and taurine together. So I asked Sachin about this. What do you think is in these energy drinks that causes these changes? That's the million dollar question.

Science! You know, I was having coffee with my brother the other day and he said there is always a point in a Science vs. episode where the scientist says, yeah, we don't really know what's going on. And I guess this is that point. Yeah, we've arrived at that point in the episode. And of course, it's also really hard to say what's going on when this is probably

very, very rare, you know? People drink energy drinks all the time and very few people land in the hospital. Okay, so here is what I think I have learned from this episode,

Rose Rimla. Tell me how I did. Let's hear it. And if I pass the test, I have a good sense of humor. Is that what we learned? Yeah. Yes.

Case closed. Caffeine truly does make me poo very quickly. It can affect your sleep, but very much dependent on genetics. So dare I say, listen to your body and not what people online might be telling you about what you should and should not do with caffeine. And meanwhile, it might reduce your risk of depression if you're drinking coffee and tea. What do you say? Cancer, Parkinson's, diabetes, and energy drinks. There is something weird about them. So if you are looking for a boost, it's safer to go with tea or coffee. How'd I do?

A plus, people. I'm not surprised. And you, as a prize, I sent a case of Prime to your house. So don't drink it all at once. Excellent. Cheers, Great. Don't drink it all at once. Excellent. Cheers, Rose. Cheers. But before you go,

Rose. Rose. Rose. I'm here. I'm still here. Okay. Okay. How many citations

are in this week's episode? This episode was the first time I've ever opened so many tabs that my browser stopped displaying them. Like, I reached the limit of how many tabs I can have open. That is so many tabs that my browser stopped displaying them. Like I reached the limit of how many tabs I can have open. That is so many tabs. It's like getting to the end of your Instagram feed.

You're like, oh, no. But what is in the script is that we have 118 citations. 118. Okay, yes. And if people want to see these citations, find out where we got all of our info from, where should they go? They can click the link in the show notes that will send them to the transcript. Excellent. And I guess while people are scrolling through Instagram and hitting the end, if you have hit the end of your Instagram, you could just come over to Science Versus. Was that a segue of like picking up social media accounts? Thanks.

Yeah. We are at science underscore VS. I'm on TikTok at Wendy Zuckerman. And we will see you next week. Thanks, Rose. Thanks, Wendy. This episode was produced by Rose Rimler with help from me, Wendy Zuckerman,

as well as Nick Delrose, Joel Werner and Michelle Dang. We're edited by Blythe Terrell. Fact-checking by Sarah Baum. Mix and sound design by Bumi Hidaka. Music written by Bobby Lord, Bumi Hidaka, Emma Munger and Peter Lennon. Special thanks to all of the researchers that we spoke to for this episode,

including Dr. Brian Saunders, Dr. Sergi Ferre, Professor Andreas Heinz, Professor Christine Curran, Dr. Erica Loftfield, Dr. Felix Oberhofer, Dr. Alan Wayne-Jones, and Dr. Vijay Yadav. Extra special thanks to Jason Bittler-Sill and the Zuckerman family. Science Versus is a Spotify Studios original. You can listen to us for free on Spotify

or wherever you get your podcasts. We are everywhere that podcasts are. I guess we're in a lot of places. If you are listening on Spotify, follow us and tap the bell icon so you can receive notifications whenever we put out a new episode. And if you like us,

wherever you are listening, please give us a five-star review. I'm Wendy Zuckerman. Back to you next time. Now, it's not all fun stuff like rectal probes. Name of your sex tape, it's not all fun and rectal probes. No, the sex tape is called

All Fun and Rectal Probes. Right. We can't only talk about rectal probes on this episode. We also unfortunately have to talk about some unpleasant stuff.