Coffee and Your Heart: Enemy or Unexpected Ally?

In clinic, whenever coffee comes up, many people tense up. The same questions appear again and again:

“Is it safe to drink coffee if I have a heart problem?”

“If I don’t drink coffee I feel exhausted—should I force myself to quit?”

It doesn’t help that media headlines often contradict one another. One day coffee is praised for lowering cancer risk and extending life; the next it’s labelled a trigger for high blood pressure and heart rhythm problems. No wonder so many people feel stuck: they enjoy coffee, feel more alert with it, yet are scared enough to wonder if they should give it up completely. This confusion is especially common in people with existing heart disease, atrial fibrillation, or hypertension, who have never been given clear guidance on how to find a reasonable middle ground.

A recent randomized clinical trial published in JAMA (Journal of the American Medical Association) took a very direct look at this issue. The researchers asked a simple but important question: among people with atrial fibrillation who already drink coffee, is it safer to keep drinking or to stop completely? The results were not what many would expect.

A Clinical Trial in Patients with Atrial Fibrillation

The study enrolled 200 patients with atrial fibrillation who were scheduled to undergo electrical cardioversion, a procedure that restores normal heart rhythm using a controlled electric shock. All participants were habitual coffee drinkers before joining the trial, so the focus was not on whether to start coffee, but on whether they should deliberately stop after cardioversion.

The design was straightforward:

• One group was randomized to completely avoid coffee for 6 months, with instructions to avoid any caffeinated coffee.

• The other group was asked to continue drinking at least one cup of caffeinated coffee per day for the same 6-month period.

At the end of the 6 months, the researchers compared how often atrial fibrillation recurred in each group:

• In the “at least one cup a day” group, 47% experienced a recurrence.

• In the “no coffee” group, 64% had atrial fibrillation again.

In other words, in this study population, those who continued to drink at least one cup of coffee daily had almost a 40% lower relative risk of recurrence over six months. The authors noted that this is one of the few randomized controlled trials directly comparing “drinking” vs “not drinking” coffee in relation to atrial fibrillation recurrence, adding a valuable piece of data to a field that has mostly relied on observational studies.

This does not mean every person with atrial fibrillation should start drinking more coffee. Rather, it suggests that for patients who already drink coffee, a blanket rule to “quit completely” may not always be more protective than continuing moderate intake.

Coffee, the Heart, and Preventive Medicine

If we focused only on this single study, it would be easy to jump to a simplistic conclusion: “If you have atrial fibrillation, it’s actually better to drink coffee.” But from a preventive medicine perspective, we always put new data back into the broader context of existing evidence and individual risk.

Large cohort studies over the past decade have repeatedly found that moderate coffee intake (about 1–3 cups per day) is associated with lower all-cause mortality and reduced cardiovascular risk. This new clinical trial zooms in on a more specific group—people with known atrial fibrillation—and suggests that complete coffee abstinence may not offer an advantage, and may even be associated with higher recurrence than maintaining at least one cup per day.

The research team proposed several possible mechanisms and clinical implications:

• Coffee is rich in polyphenols and other antioxidant compounds that may improve endothelial function (how well blood vessels dilate) and reduce oxidative stress, both of which can create a more stable electrical environment in the heart.

• Moderate coffee intake can increase alertness and support exercise performance. Regular physical activity is itself a well-established protective factor against atrial fibrillation recurrence, so coffee may play a supporting role here.

• Many coffee drinkers use coffee in place of sugar-sweetened beverages or high-calorie drinks. Over time, this pattern can translate into a healthier overall diet and lower cardiometabolic risk.

Taken together, these data argue for a more nuanced view. For some heart patients, stable, moderate coffee intake may not be a major risk factor at all, and in specific contexts might fit reasonably within a heart-healthy lifestyle, rather than being automatically banned.

Who Can Drink Coffee—and How?

The first major source of individual difference is metabolism and genetics. The body mainly breaks down caffeine through an enzyme called CYP1A2:

• People who metabolize caffeine quickly clear it from their system faster and tend to have lower risks of palpitations, blood pressure spikes, and insomnia at moderate doses.

• People who metabolize caffeine slowly have caffeine in their system for longer. Their heart and nervous system can be more sensitive, so even a single cup may trigger a racing heartbeat, dizziness, or difficulty sleeping.

This helps explain why some people can drink three cups a day and sleep soundly, while others toss and turn all night after half a cup in the afternoon. From an individualized care standpoint, the same “one cup of coffee” can have very different risk–benefit profiles depending on the person.

The second important factor is what kind of coffee you’re actually drinking:

• Hand-brewed coffee, espresso, or plain black coffee with a splash of milk mainly deliver caffeine and polyphenols, with relatively controlled calories and sugar.

• Three-in-one mixes, heavy-sugar lattes, and drinks loaded with creamer, syrups, and whipped cream are a different story. In those cases, the main cardiovascular and metabolic burden often comes not from the coffee itself, but from the “extras” added around it.

The third layer is overall health and daily context. Certain situations call for more caution:

• Significant insomnia or anxiety, where nighttime sleep is already fragile.

• Poorly controlled blood pressure, with large fluctuations and frequent symptoms such as headaches, chest tightness, or dizziness.

• Severe gastroesophageal reflux, where coffee reliably causes heartburn or upper abdominal discomfort.

In these settings, the potential downsides of coffee may outweigh any theoretical benefits, and it makes sense to be more conservative about daily dose, timing, and strength. On the other hand, if someone has reasonably stable sleep, manages stress well, eats and moves in a health-conscious way, and does not experience palpitations or other symptoms with coffee, moderate intake is more likely to function as a “small bonus” rather than a major risk driver.

So instead of asking, “Is coffee good or bad?” a more useful question is:Given my genes, health conditions, daily schedule, and stress level, how can I include coffee—if at all—in a way that supports rather than undermines my overall health?

Key Takeaways

This JAMA trial in patients with atrial fibrillation who were habitual coffee drinkers suggests that, in this group, completely avoiding coffee was not clearly safer than continuing at least one cup of caffeinated coffee per day. Over six months, those who kept drinking coffee actually had fewer recurrences of atrial fibrillation than those who quit.

That does not mean everyone should drink more coffee. Instead, it challenges the idea that a strict “no coffee” rule is always the best or safest approach. The real decision depends on:

• Your cardiovascular profile and overall risk.

• How your body metabolizes caffeine.

• Your day-to-day stress and sleep patterns.

• The type of coffee and how it is prepared.

Rather than focusing only on whether to “quit completely,” it is more helpful to first stabilize the foundations—sleep, diet quality, movement, and stress management—and then, on top of that, decide what role coffee should play. The goal is to find a level and style of coffee intake that helps you stay clear-headed and enjoy your day, while allowing your heart and metabolism to stay as steady and healthy as possible.

Reference

Wong, Christopher X et al. “Caffeinated Coffee Consumption or Abstinence to Reduce Atrial Fibrillation: The DECAF Randomized Clinical Trial.” JAMA, 10.1001/jama.2025.21056. 9 Nov. 2025, doi:10.1001/jama.2025.21056