Posted on 08/23/2025 8:24:25 PM PDT by SeekAndFind
For years if not decades, coffee lovers everywhere have been confused.
While growing research has linked our favorite morning drink to numerous health benefits from reduced inflammation to lower risk of serious diseases, like cancer, diabetes and Parkinson’s disease, doctors have still warned against its high levels of caffeine.
Why?
Well, the theory has long been that the caffeine that gives your brain a jolt to get you started each morning might also give your heart a jolt that could cause rhythm problems, such as atrial fibrillation (AFib).
So what’s a coffee lover to do?
Well, rather than giving up your cup of joe, sit back and enjoy because a huge research endeavor has finally found the answer…
A team of investigators at UC San Francisco took a deep dive into all things coffee and arrhythmia. In fact, they conducted the largest study of its kind — following 386,258 coffee drinkers and publishing their results in JAMA Internal Medicine.
They not only looked at self-reported coffee consumption as a predictor of future arrhythmias, they went a step further. The investigators utilized a technique called “Mendelian Randomization”, which allowed them to leverage genetic data to help determine the cause behind any arrhythmias that did develop, rather than just blaming them on coffee (like past studies may have done).
They then followed up on each participant for an average of four years.
The good news? They found zero evidence that coffee consumption raises the risk of any form of arrhythmia.
In fact, their results show just the opposite effect…
The team discovered that drinking higher amounts of coffee was associated with a three percent reduced risk of developing an arrhythmia , including atrial fibrillation, premature ventricular contractions or other common heart conditions.
As senior author Gregory Marcus, MD, professor of medicine in the Division of Cardiology at UCSF, puts it, “We found no evidence that caffeine consumption leads to a greater risk of arrhythmias. Our population-based study provides reassurance that common prohibitions against caffeine to reduce arrhythmia risk are likely unwarranted.”
Still, you may not want to go overboard on the amount of java you drink. Another study found a good reason for you to keep your coffee consumption to under six cups a day — avoiding stroke and dementia.
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Been drinking coffee every morning for decades. Big cup of half-caf. It started tasting horrible to me a month ago so quit.
Gave my coffee to a friend and now drinking green tea. Don’t love it either, but it tastes better than coffee IMHO. Put a little stevia and pasture-raised 2% milk in it and it’s not all that bad.
Read here recently that green tea has health benefits, different ones than coffee has.
Baloney. I used to get heart rhythm changes as soon as I drank coffee. My doctor had me drink a cup and then did some EKGs and told me “no more coffee for you!”.
I am an engineer. We live on coffee! As one poster on FR stated last month: “If I don’t drink enough coffee, how am I supposed to have enough red blood cells for my caffeine system?”
Good experimental information. Thanks.
Three shots of espresso after breakfast and dinner. No milk or sugar.
Same here. Palpitations would start after 4 cups of Joe/
This has been known for many years.
It is caused as the caffeine in coffee degrades the diamine oxidase enzyme in the blood, the primary enzyme that degrades histamines in the body.
There are four types of histamine receptors in the heart, including in the AV node which regulates the heartbeat.
Histamine influences the heart’s AV node via both H1-receptors and H2-receptors.
Stimulation of H1-receptors slows AV node conduction (negative dromotropic effect), while H2-receptors can shorten conduction time (positive dromotropic effect), though the H1-mediated negative effect is often dominant.
The overall effect depends on the balance between H1 and H2 receptor activation and histamine concentrations.
The H1 histamine receptor’s inhibitory impact on AV node signal transduction is a key aspect of histamine’s action on heart rhythm.
When I cut back on caffeine and took a diamine oxidase enzyme supplement, my arrhythmia stopped immediately.
Think of the AV node as the heart’s pacemaker that acts like a capacitor on an electric motor. It holds the electric charge coming from the SA node in the right atrium and releases it at a sufficient level to cause muscle contraction, especially in the left ventricle to pump blood throughout the body.
This is also how Covid decreases the heart’s pumping ability. It decreases the electric charge flowing from the AV node through the HIS and Perkinje fibers, thus decreasing the strength of muscle contraction.
“When I cut back on caffeine and took a diamine oxidase enzyme supplement, my arrhythmia stopped immediately.”
600 mgs Magnesium with 3,000 mgs Vitamin C every night at bedtime and I drink 5 cups of real strong coffee before noon every morning.
I do know the Vitamin C helps manage the histamine release considerably.
800-1200mg a day
Mostly diet Sun drop
Born bad heart and his bundle eventual trifascicular block
Never palpitations
“I am an engineer. We live on coffee!”
I don’t think it’s an accident that caffeine’s introduction into western civilization ~500 years ago and its subsequent transition to near-universal consumption coincided with technological revolutions that dwarfed those of previous millennia of human history. To a great extent, caffeine is a wonder drug, increasing the performance of the human brain beyond its natural capacity.
Yes, vitamins C is a natural antihistamine and helps to stabilize histamine levels. It also causes the mast cells throughout the body to release less histamine.
It supports the production of the diamine oxidase enzyme in the body.
Strong heart, no family history of heart problems. Rarely drink more than four or five per day, pots that is. All day long, right up to bed time.
I usually drink a 12 cup pot (which is 12, 6 oz cups)of Peet’s Dark French Roast (freshly ground beans) every day. I start at 5:30AM every morning and am usually done drinking coffee by noon. I drink it black and bitter. Never noticed any problems related to coffee and neither have my cardiologists, or at least they’ve never said anything about cutting back when I tell them. I do have to take blood pressure medication, 5mg of Bisoprolol a day. Keeps my blood pressure at 120/70 pretty consistently.
“Death Before Decaf “
For sure!
I used to drink a lot of coffee - these days, I stick with 2 cups in the morning - I’d rather get my energy from good diet and exercise, so I also stay away from them “energy” drinks which give a false sense of “vigor/alertness”...
It’s an addiction and a habit. I am addicted to one cup of coffee a day. Makes me feel I reward myself for getting out of bed. And I need the exercise, too. Without that, my brain slows down.
Blah, blah, blah! 🙄
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