Poor title. This is specific to patients who already underwent cardioversion (shocking the heart back into normal rhythm) AND were habitual coffee drinkers, who now have reduced coffee to 1 cup/day rather than sudden complete abstinence. Recurrence at 6 months was 47% instead of 64%. And this only applies to those who don't have clear caffeine-associated episodes.
To add more information, the intervention was guidance about caffeine intake. From the Methods:
> If allocated to caffeinated coffee consumption, patients were encouraged to drink at least 1 cup of caffeinated coffee (or at least 1 espresso shot) and other caffeine-containing products every day as per their usual lifestyle. It was recommended that patients in the coffee consumption group not intentionally increase or decrease consumption of coffee or other caffeine-containing products.
> If allocated to the abstinence group, patients were encouraged to completely abstain from coffee, including decaffeinated coffee, and other caffeine containing products.
The people who were selected into the study were not necessarily "habitual coffee drinkers". The only requirement was "was a habitual coffee drinker sometime in the past five years". The difference between the two is subtle, but its possible there were people in the study who had already abstained for some amount of time.
> If allocated to caffeinated coffee consumption, patients were encouraged to drink at least 1 cup of caffeinated coffee (or at least 1 espresso shot) and other caffeine-containing products every day as per their usual lifestyle
I tried to skim to figure out how much caffeine/ml was actually in the drinks, but seems the researchers don't know themselves either? Wouldn't there be a huge difference depending on the beans, how it's made and so on? 1 espresso can be made very strong with packed coffee, or it can be made very weak, "1 cup of caffeinated coffee" basically says nothing at all, unless I'm missing the true definition elsewhere in the paper.
James Hoffman did some interesting videos on that -- espresso is a more efficient extraction method than Aeropress, but less complete than a very high water to coffee ratio pour over for the same weight of ground coffee. Extraction of caffeine is very directly tied to contact time and temperature, so two double shots of espresso (40g coffee) can actually be less caffeine extracted than a single large pour over (25g coffee) when the pour over is upwards of 22% extraction (typical of 20:1 water to coffee ratios and modern zero-bypass brewers). Similarly, there are large differences in beans, so 22% extraction on weak caffeine beans might be way less than 18% extraction on much higher caffeine beans. This is most obvious in the fact that Robusta has much higher caffeine on average than Arabica. Also, 22% extraction has a lot more unpleasant bitter compounds, not just more caffeine, so it's not my preference for taste in general.
Yes, but it might also be that you're drinking "coffee" (I assume you mean drip / pour-over) in the morning when you are just out of bed and have almost nothing in your stomach. Whereas the espresso you're drinking at a shop later in the day, probably already with breakfast in your stomach and maybe you're ordering a snack with it.
> A high carbohydrate meal consumed prior to caffeine ingestion significantly reduced serum caffeine concentrations and delayed time to peak concentration
Caffeine is a stimulant, acting on the sympatheitc nervous system. If you're also activating the parasympathetic nervous system, like by eating a meal, the effect won't be as strong.
Another effect of caffeine is as an adenosine re-uptake antagonist. Adenosine levels are usually low in the morning, so the effect is small. Later in the day, it can have a bigger effect on how alert you feel.
As an espresso drinker with a good machine and grinder, and lots of variety with mostly Italian beans, it depends, as the OP already indicated. I only buy low or at most middle caffein content beans to begin with, but you can get high caffeine beans for espresso easily. Easiest method: Increase the amount of Robusta.
Good vendors should have things like caffein content in their product description. I mostly buy from an online vendor that lists the exact roast date and also shows caffein content for each product (https://www.espresso-international.com/ - their only disadvantage is the use of some pretty light GRAY for most text, another topic, too many websites do this for reasons I cannot understand).
Many years ago, when I still lived in the Bay Area, the Cappuccino I got at a certain Berkeley coffee shop always made my heart go BOOM BOOM BOOM. Whatever concoction they brewed certainly had very high caffein (and I hated it, but the place was great). The ones I make myself now I can drink at 10 pm and be completely fine (I only drink 2-4 max espresso per day, and can easily drink zero if I'm away and have no access to good espresso, so I'm not addicted and just "used to it").
Sometimes I compromise and buy medium caffein beans when it's something good, but those I can feel just a little.
All of that just means you have to exert some control over which beans you consume, if you want to keep caffein low. On the plus side, if you stick to 80%-100% Arabica (the rest Robusta) it's not hard at all. If you like mixes with high Robusta ratio it gets much harder. Caffein free roasts exist though (examples: https://www.espresso-international.com/decaffeinated-coffee), but that choice severely limits your options.
No the cappuccino tasted fine, good even. I hated the effect on my heart that came later.
Also, the food was very very good, I still dream of it occasionally. Just some sandwiches, but perfection. Some cooked root whose name I forgot as the main ingredient, the overall composition was what distinguished it though, like a cook is able to get much more than the sum of the parts out of the ingredients by choosing compatible ones and doing appropriate processing.
Also, top location. College Ave. somewhere, not University Ave, maybe corner Ashby, and ca. twenty to twenty-five years ago.
The biggest thing is what kind of "coffee" you mean by coffee -- cold brew in particular tends to be a much higher extraction % since the bitter notes you get on higher extractions are less noticeable at colder temperatures. The rest is what the sibling responses mention -- time of day and speed of absorption in the digestive system can have big impacts.
I researched this a bit and found there really is no standardized "cup of coffee" for research purposes. Even for volume, I've seen it range from 6 to 12 fl oz. The main mechanisms of action are caffeine and flavonoids, and there's so much variation across beans and brewing methods that you'd think researchers would try to include that in their data to normalize it.
They were advised to drink at least one cup per day IIUC / maintain their current lifestyle. So there is no consistent amount, but it’s still meaningful vs being advised not to have any caffeine.
It's probably whatever "1 cup" means to the patient. The researchers would want them to stick to their status quo for the best results.
For example, 1 cup of coffee for my wife involves a blend of coffee and espresso beans with no adders, but 1 cup to her dad means lighter roast bean with milk. Both options have different caffeine contents and nutritional values.
A weak espresso sounds like you're just making a small amount of American/German coffee. How could that be passed of as an espresso? It's not just a measure of volume.
> "1 cup of caffeinated coffee" basically says nothing at all
Frankly, no. 1 cup of caffeinated coffee is on average significantly more caffeine than 0 cups, which is all you need for sufficient n. The only confounding variable to worry about here is whether caffeine is entering the diets of the two experimental groups at different rates via other channels (e.g., are the people who are forbidden to drink coffee drinking more tea to compensate?), though even this effect, if present, would likely tend to decrease the separation of the outcome distributions and is thus a low threat to validity.
People obsess over precision when it is often one of the least important aspects of an experiment. The outcomes of studies like this are in practice absolutely dependent on quality and rates of compliance. Choosing an uncomplicated treatment that is easy and natural for subjects to comply with is not merely acceptable but in fact a massively better design than complex protocols involving precisely measured quantities of lab-grown coffee in vials that can be misplaced, forgotten, deliberately shunned, etc. Also in this case the treatment corresponds closely to the real-world situation that the research is attempting to learn about.
I've been doing my own personal experiments on myself trying to reduce caffeine intake to help with stress and anxiety. I've felt much better with just a small cutting back of my caffeine intake by taking my "main" cup of coffee (12oz cup) in the morning like I usually do and then just drinking 1/3 caffeinated, 2/3 decaf the rest of the day and going full decaf after 2pm if I have any at all.
I used to drink minimum 36oz (~150mg of caffeine per cup) of coffee per day and it was just turning me into an absolute wreck and just cutting back that little bit has made a huge difference. So instead of 450mg of caffeine, I'm getting ~270mg, so just a little above half the intake and it's made a huge difference.
A-fib just seemed like a natural consequence of the "caffeine peak" and reducing my consumption helped quite a bit.
Note that study suggests that coffee consumption decreases arrhythmia. (The title is horribly confusing, I know.)
From a quick skim, the protocol seemed to be “advise the patient to drink at least one cup of coffee per day or continue drinking your usual amount.” So it seems the results don’t track with your experience (or my own experience of improved stress and happiness when I cut down on coffee) which is why I think it’s surprising / possibly a fluke.
I, too, have found that in the presence of a-fib, the optimal amount of caffeine is not zero; but I must think that every patient is different. Most people with diagnosed a-fib also take a beta blocker, and I (just only me) found that an excess of the beta blocker had paradoxical effects. So there is another potential interaction. Then, I also voted myself a small dose of OTC lithium, and subjectively derived obvious and substantial benefit from it, but there is (as yet) no science behind that, so I will not assert causation.
I have afib and have been cardioverted once ~4 years ago. Own a kardia ekg and a regular blood pressure cuff. Coffee increases my pulse, but the waveform remains normal. Alcohol is the real killer, a very small amount like a beer will immediately show in ekg waveform abnormalities. Enough to get a buzz and it's a warzone let alone actually drunk. It's also surprising how long it lasts even into the hungover and no longer drunk zone. I'm not a doctor, but I would personally recommend to cut out all drinking with an occurrence of afib and yes, this is conjecture, but any sort of heart condition. I'm also not being sponsored by kardia and am creeped out by it storing my data presumably on the cloud.
I definitely get a skipped beat arrhythmia when I’m hung over. Noticed it in my 30s. 15 years of amphetamine use prob didn’t help. Thankfully I only drink when I’m single, so I’ve had a nice break.
Weird story: I bought a Kardia when I was having mystery arrhythmia. At its worst, a half cup of coffee would trigger it, but at that point I suspect the anxiety of getting it was also a trigger.
It was caused by a minoxidil+finasteride spray I was applying to my head for a year. It slowly got worse over time so it took me way too long to suspect it.
The quick summary is that being advised to drink coffee (for habitual coffee drinkers with arrhythmia) leads to less arrhythmia, not more. This is surprising since caffeine is a stimulant and usually thought to be pro-arrhythmic.
love to hear good news even if it's a relatively small sample size. anecdotal, but i've heard that the antioxidants in fresh ground coffee is also very good!
The title does not match the conclusion. I would like to see lifetime abstainers from caffeine vs regular coffee drinkers. Remember caffeine is a form of a neurotoxin.
In the context of HN, the title is fairly misleading.
Suggestion: Got to the article, hit PgDn a few times, and look at the "Visual Abstract" graphic - which is both very short, and packed with important details.
Poor title. This is specific to patients who already underwent cardioversion (shocking the heart back into normal rhythm) AND were habitual coffee drinkers, who now have reduced coffee to 1 cup/day rather than sudden complete abstinence. Recurrence at 6 months was 47% instead of 64%. And this only applies to those who don't have clear caffeine-associated episodes.
To add more information, the intervention was guidance about caffeine intake. From the Methods:
> If allocated to caffeinated coffee consumption, patients were encouraged to drink at least 1 cup of caffeinated coffee (or at least 1 espresso shot) and other caffeine-containing products every day as per their usual lifestyle. It was recommended that patients in the coffee consumption group not intentionally increase or decrease consumption of coffee or other caffeine-containing products.
> If allocated to the abstinence group, patients were encouraged to completely abstain from coffee, including decaffeinated coffee, and other caffeine containing products.
> including decaffeinated coffee
Sounds like the cause could also be some other substance than caffeine? Decaf still contains various other alkaloids.
The people who were selected into the study were not necessarily "habitual coffee drinkers". The only requirement was "was a habitual coffee drinker sometime in the past five years". The difference between the two is subtle, but its possible there were people in the study who had already abstained for some amount of time.
> If allocated to caffeinated coffee consumption, patients were encouraged to drink at least 1 cup of caffeinated coffee (or at least 1 espresso shot) and other caffeine-containing products every day as per their usual lifestyle
I tried to skim to figure out how much caffeine/ml was actually in the drinks, but seems the researchers don't know themselves either? Wouldn't there be a huge difference depending on the beans, how it's made and so on? 1 espresso can be made very strong with packed coffee, or it can be made very weak, "1 cup of caffeinated coffee" basically says nothing at all, unless I'm missing the true definition elsewhere in the paper.
James Hoffman did some interesting videos on that -- espresso is a more efficient extraction method than Aeropress, but less complete than a very high water to coffee ratio pour over for the same weight of ground coffee. Extraction of caffeine is very directly tied to contact time and temperature, so two double shots of espresso (40g coffee) can actually be less caffeine extracted than a single large pour over (25g coffee) when the pour over is upwards of 22% extraction (typical of 20:1 water to coffee ratios and modern zero-bypass brewers). Similarly, there are large differences in beans, so 22% extraction on weak caffeine beans might be way less than 18% extraction on much higher caffeine beans. This is most obvious in the fact that Robusta has much higher caffeine on average than Arabica. Also, 22% extraction has a lot more unpleasant bitter compounds, not just more caffeine, so it's not my preference for taste in general.
Coffee makes me jittery but espresso (or lattes) do not. Is this why?
Yes, but it might also be that you're drinking "coffee" (I assume you mean drip / pour-over) in the morning when you are just out of bed and have almost nothing in your stomach. Whereas the espresso you're drinking at a shop later in the day, probably already with breakfast in your stomach and maybe you're ordering a snack with it.
why would it matter what's in your stomach? caffeine goes pretty quickly to the blood stream, right?
> A high carbohydrate meal consumed prior to caffeine ingestion significantly reduced serum caffeine concentrations and delayed time to peak concentration
https://www.sciencedirect.com/science/article/abs/pii/S14402...
Caffeine is a stimulant, acting on the sympatheitc nervous system. If you're also activating the parasympathetic nervous system, like by eating a meal, the effect won't be as strong.
Another effect of caffeine is as an adenosine re-uptake antagonist. Adenosine levels are usually low in the morning, so the effect is small. Later in the day, it can have a bigger effect on how alert you feel.
I heard that the anxiety from caffeine is worse when you haven’t eaten. No time to check resources for that at the moment
having a full stomach has a moderating effect on most drug uptake.
Maybe?
As an espresso drinker with a good machine and grinder, and lots of variety with mostly Italian beans, it depends, as the OP already indicated. I only buy low or at most middle caffein content beans to begin with, but you can get high caffeine beans for espresso easily. Easiest method: Increase the amount of Robusta.
Good vendors should have things like caffein content in their product description. I mostly buy from an online vendor that lists the exact roast date and also shows caffein content for each product (https://www.espresso-international.com/ - their only disadvantage is the use of some pretty light GRAY for most text, another topic, too many websites do this for reasons I cannot understand).
Many years ago, when I still lived in the Bay Area, the Cappuccino I got at a certain Berkeley coffee shop always made my heart go BOOM BOOM BOOM. Whatever concoction they brewed certainly had very high caffein (and I hated it, but the place was great). The ones I make myself now I can drink at 10 pm and be completely fine (I only drink 2-4 max espresso per day, and can easily drink zero if I'm away and have no access to good espresso, so I'm not addicted and just "used to it").
Sometimes I compromise and buy medium caffein beans when it's something good, but those I can feel just a little.
All of that just means you have to exert some control over which beans you consume, if you want to keep caffein low. On the plus side, if you stick to 80%-100% Arabica (the rest Robusta) it's not hard at all. If you like mixes with high Robusta ratio it gets much harder. Caffein free roasts exist though (examples: https://www.espresso-international.com/decaffeinated-coffee), but that choice severely limits your options.
> (and I hated it, but the place was great)
That's a mystifying statement. Why go if you found the coffee so unpleasant?
Decor?
No the cappuccino tasted fine, good even. I hated the effect on my heart that came later.
Also, the food was very very good, I still dream of it occasionally. Just some sandwiches, but perfection. Some cooked root whose name I forgot as the main ingredient, the overall composition was what distinguished it though, like a cook is able to get much more than the sum of the parts out of the ingredients by choosing compatible ones and doing appropriate processing.
Also, top location. College Ave. somewhere, not University Ave, maybe corner Ashby, and ca. twenty to twenty-five years ago.
The biggest thing is what kind of "coffee" you mean by coffee -- cold brew in particular tends to be a much higher extraction % since the bitter notes you get on higher extractions are less noticeable at colder temperatures. The rest is what the sibling responses mention -- time of day and speed of absorption in the digestive system can have big impacts.
Espresso beans typically have different (darker) roast profile from filter so some of it maybe due to that
That or there is no robusta in your espresso.
I researched this a bit and found there really is no standardized "cup of coffee" for research purposes. Even for volume, I've seen it range from 6 to 12 fl oz. The main mechanisms of action are caffeine and flavonoids, and there's so much variation across beans and brewing methods that you'd think researchers would try to include that in their data to normalize it.
Caffeine, flavonoids and monoamine oxidase inhibitors.
They were advised to drink at least one cup per day IIUC / maintain their current lifestyle. So there is no consistent amount, but it’s still meaningful vs being advised not to have any caffeine.
It's probably whatever "1 cup" means to the patient. The researchers would want them to stick to their status quo for the best results.
For example, 1 cup of coffee for my wife involves a blend of coffee and espresso beans with no adders, but 1 cup to her dad means lighter roast bean with milk. Both options have different caffeine contents and nutritional values.
There’s an average amount in the average cup of coffee.
A weak espresso sounds like you're just making a small amount of American/German coffee. How could that be passed of as an espresso? It's not just a measure of volume.
> "1 cup of caffeinated coffee" basically says nothing at all
Frankly, no. 1 cup of caffeinated coffee is on average significantly more caffeine than 0 cups, which is all you need for sufficient n. The only confounding variable to worry about here is whether caffeine is entering the diets of the two experimental groups at different rates via other channels (e.g., are the people who are forbidden to drink coffee drinking more tea to compensate?), though even this effect, if present, would likely tend to decrease the separation of the outcome distributions and is thus a low threat to validity.
People obsess over precision when it is often one of the least important aspects of an experiment. The outcomes of studies like this are in practice absolutely dependent on quality and rates of compliance. Choosing an uncomplicated treatment that is easy and natural for subjects to comply with is not merely acceptable but in fact a massively better design than complex protocols involving precisely measured quantities of lab-grown coffee in vials that can be misplaced, forgotten, deliberately shunned, etc. Also in this case the treatment corresponds closely to the real-world situation that the research is attempting to learn about.
> The DECAF Randomized Clinical Trial
> The DECAF (Does Eliminating Coffee Avoid Fibrillation?) trial...
Fantastic naming.
Cardiologists pride themselves on the best acronyms in study titles I think. There's a lot of good ones out there.
That warms my heart.
I've been doing my own personal experiments on myself trying to reduce caffeine intake to help with stress and anxiety. I've felt much better with just a small cutting back of my caffeine intake by taking my "main" cup of coffee (12oz cup) in the morning like I usually do and then just drinking 1/3 caffeinated, 2/3 decaf the rest of the day and going full decaf after 2pm if I have any at all.
I used to drink minimum 36oz (~150mg of caffeine per cup) of coffee per day and it was just turning me into an absolute wreck and just cutting back that little bit has made a huge difference. So instead of 450mg of caffeine, I'm getting ~270mg, so just a little above half the intake and it's made a huge difference.
A-fib just seemed like a natural consequence of the "caffeine peak" and reducing my consumption helped quite a bit.
Note that study suggests that coffee consumption decreases arrhythmia. (The title is horribly confusing, I know.)
From a quick skim, the protocol seemed to be “advise the patient to drink at least one cup of coffee per day or continue drinking your usual amount.” So it seems the results don’t track with your experience (or my own experience of improved stress and happiness when I cut down on coffee) which is why I think it’s surprising / possibly a fluke.
I've found great difference in how I feel based on the source of caffeine.
From best to worst, for me: Yerba mate > healthi-ish energy drinks > white/green/black tea > coffee.
Coffee almost always results in significant anxiety (at same caffeine dose), jitteriness, and acid reflux. Yerba mate is by far the best for me.
> healthi-ish energy drinks
No such thing!
lol, I get it. But they do exist, such as https://www.lifeaidbevco.com/blends/focus
Me too, less caffeine means less stress and anxiety for me.
The key is to find other warm beverages to drink and get protein and sugar into you in the morning.
We've been loving Golden Lattes!
Have you compared any other factors? I find that my most consistent factor for a-fib is dehydration.
I would say it does. Lots of things improve overall when I am sufficiently hydrated...but I pee way more lol
I, too, have found that in the presence of a-fib, the optimal amount of caffeine is not zero; but I must think that every patient is different. Most people with diagnosed a-fib also take a beta blocker, and I (just only me) found that an excess of the beta blocker had paradoxical effects. So there is another potential interaction. Then, I also voted myself a small dose of OTC lithium, and subjectively derived obvious and substantial benefit from it, but there is (as yet) no science behind that, so I will not assert causation.
I have afib and have been cardioverted once ~4 years ago. Own a kardia ekg and a regular blood pressure cuff. Coffee increases my pulse, but the waveform remains normal. Alcohol is the real killer, a very small amount like a beer will immediately show in ekg waveform abnormalities. Enough to get a buzz and it's a warzone let alone actually drunk. It's also surprising how long it lasts even into the hungover and no longer drunk zone. I'm not a doctor, but I would personally recommend to cut out all drinking with an occurrence of afib and yes, this is conjecture, but any sort of heart condition. I'm also not being sponsored by kardia and am creeped out by it storing my data presumably on the cloud.
I definitely get a skipped beat arrhythmia when I’m hung over. Noticed it in my 30s. 15 years of amphetamine use prob didn’t help. Thankfully I only drink when I’m single, so I’ve had a nice break.
Weird story: I bought a Kardia when I was having mystery arrhythmia. At its worst, a half cup of coffee would trigger it, but at that point I suspect the anxiety of getting it was also a trigger.
It was caused by a minoxidil+finasteride spray I was applying to my head for a year. It slowly got worse over time so it took me way too long to suspect it.
The trick with a kardia is to look away when you run the test. I try to look out a window or something.
The quick summary is that being advised to drink coffee (for habitual coffee drinkers with arrhythmia) leads to less arrhythmia, not more. This is surprising since caffeine is a stimulant and usually thought to be pro-arrhythmic.
love to hear good news even if it's a relatively small sample size. anecdotal, but i've heard that the antioxidants in fresh ground coffee is also very good!
The title does not match the conclusion. I would like to see lifetime abstainers from caffeine vs regular coffee drinkers. Remember caffeine is a form of a neurotoxin.
In the context of HN, the title is fairly misleading.
Suggestion: Got to the article, hit PgDn a few times, and look at the "Visual Abstract" graphic - which is both very short, and packed with important details.
Imagine being assigned to the decaf arm of this study. I'd be mad.