Coffee, Caffeine, and AFib: The Evidence That Upends Decades of Caution

R.E. Hengsterman
4 days ago
2 min read

Hand with pink nails holding a white cup of coffee on a saucer with a spoon. A small plant in a glass jar sits on a wooden table by a window.

For years, many of us assumed caffeine and AFib were inseparable. The belief made sense: palpitations after a strong coffee, the long-standing warnings from clinicians, and decades of patient education that framed caffeine as a trigger. But the data has never been as straightforward as the narrative.

And when you examine the age-stratified prevalence, the pattern is unmistakable:

Ages 65–69: Prevalence varies widely across studies, but ranges around 3–6% overall, with men consistently higher than women. Some cohorts report extremely elevated male percentages due to small denominators or highly comorbid samples.
Ages 70–79: Prevalence climbs into the 5–9% range for the general population.
Ages 80+: The curve steepens. AFib becomes a condition of aging hearts—10–17% in most large datasets, and up to 25% in people near age 90. Some studies show men ≥85 with rates above 28%.
Lifetime: Roughly 1 in 4 adults will develop AFib by their sixties, regardless of sex, according to the Framingham Heart Study.

These are the drivers of AFib—aging atrial tissue, hypertension, diabetes, obesity, heart failure, and coronary disease—not coffee.

The New Twist: Coffee Might Actually Reduce AFib Risk

A new study has upended decades of reflexive caution. The DECAF Trial, led by UCSF and the University of Adelaide (published Nov 2025 in JAMA), followed 200 patients with persistent AFib or atrial flutter undergoing cardioversion.

Participants were randomized to:

Drink at least one cup of caffeinated coffee daily OR
Avoid caffeine altogether for six months.

The outcome surprised nearly everyone: Daily coffee cut AFib recurrence by 39%.

Not increased—reduced.

Why would coffee help?

1. Increased activity levels Caffeine modestly boosts physical activity, and higher activity is consistently linked to lower AFib risk.

2. Mild diuretic effect Lower intravascular volume and improved blood pressure regulation could reduce atrial stretch—one of the known mechanical contributors to AFib.

3. Anti-inflammatory compounds Coffee is rich in polyphenols and antioxidants; chronic inflammation is a well-known AFib accelerant.

4. Substitution effect Participants drinking coffee consumed fewer sugary or high-calorie beverages—another indirect benefit.

Gregory Marcus, MD, MAS, senior author and electrophysiologist at UCSF, summarized it simply:

Coffee is not only safe for most patients with AFib—it may actually be protective.

What This Means for Patients—and for the Narrative

For decades, healthcare messaging lumped all stimulants together and treated them as arrhythmia triggers. The truth is more nuanced:

Caffeine is not the same as energy drinks. The problem has often been the additives—taurine, guarana, sugar—not the caffeine itself.
Caffeine sensitivity varies by genotype and baseline cardiovascular function.Some individuals experience palpitations at lower doses, but that doesn’t equal structural arrhythmia.
The evidence is shifting toward coffee as cardioprotective, not cardiotoxic.