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.
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.
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.
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.
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.
Imagine being assigned to the decaf arm of this study. I'd be mad.
> 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?
7 replies →
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.
> The DECAF Randomized Clinical Trial
> The DECAF (Does Eliminating Coffee Avoid Fibrillation?) trial...
Fantastic naming.
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.
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!
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.
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.
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.