Coffee is part of everyday life for many people. The belief that coffee raises blood pressure and causes cardiac arrhythmia is widespread. But what are the facts?
Coffee and blood pressure—less problematic than previously thought
Many people assume that coffee significantly increases blood pressure. In the short term, caffeine can indeed cause a slight rise in blood pressure—but this effect is not very pronounced and disappears completely with regular consumption. Observational studies and meta-analyses show that regular coffee consumption (up to 4–5 cups per day!) does not increase blood pressure in the long term.
No negative effects were found for people with stable hypertension either. no negative influence. The decisive factor is regularity: those who drink coffee every day are less sensitive to the increase in blood pressure than those who only consume coffee occasionally.
Coffee and cardiac arrhythmia – not so bad after all!
For a long time, it was assumed that coffee caused cardiac arrhythmias such as extrasystoles or atrial fibrillation. However, large studies paint a different picture. In 2023, a study was published in the New England Journal of Medicine that examined the number of daily extrasystoles in relation to coffee consumption. The result: no increase in arrhythmias due to coffee – neither in so-called ventricular (from the heart chamber) nor supraventricular (from the atria) extrasystoles. See Marcus et al. https://www.nejm.org/doi/full/10.1056/NEJMoa2204737
Now, in November 2025, a new study was presented at the American Heart Association Congress: the so-called DECAF study (international, multicenter, open-label randomized). Two hundred adults (average age 69 years; 71% men) with atrial fibrillation participated, who normally drank about 1 cup of coffee per day beforehand. After successful treatment of atrial fibrillation with conversion (electrical or pharmacological) to a normal rhythm (sinus rhythm), the participants were divided in a 1:1 ratio into either a coffee group, which continued to drink about 1 cup of coffee per day, or an abstinence group, which completely abstained from caffeine for 6 months. The remaining medications were continued unchanged. The consumption of coffee and other caffeinated beverages was recorded. During the 6-month observation period, clinically detectable recurrences of atrial fibrillation/atrial flutter lasting at least 30 seconds were recorded.
Surprisingly, recurrences of atrial fibrillation or atrial flutter were less common in the coffee group (47%) than in the group abstaining from caffeine (64%), which means a 39% lower risk of recurrence of atrial fibrillation. This means that for people who already drink coffee, continuing to consume caffeinated beverages does not appear to be a problem, even if they are prone to atrial fibrillation. However, there are people who report experiencing atrial fibrillation when consuming caffeinated beverages, and they should of course refrain from doing so.
As a reminder, in January 2025, a large study involving 2,400 participants was published, which found that coffee drinkers (>5 cups per day) performed better on mental tests and had a cognitive age that was 6.7 years younger than the others. Since atrial fibrillation is associated with an increased incidence of dementia, patients with atrial fibrillation should really drink coffee regularly (see Barbagallo et al. https://www.ahajournals.org/doi/epub/10.1161/JAHA.124.034365
Please note: This applies to coffee and not to alcohol: Even small amounts of alcohol can increase the risk of atrial fibrillation...and alcohol consumption is clearly associated with dementia.
Very high amounts of caffeine (energy drinks, capsules, >10 cups per day), on the other hand, can lead to restlessness, a sharp increase in heart rate, palpitations, or dangerous arrhythmias. Caffeine intoxication can occur, but this requires extreme doses.
Coffee has effects that can be quite helpful in everyday life:
- increased alertness, faster reaction time, improved concentration
- improved mood
- slightly increased physical performance
- In some cases, relief from migraines, low risk of Alzheimer's disease, improved cognitive abilities in old age
- Increase in endurance, minimal increase in strength
- Mild positive metabolic effects, increased intestinal activity, etc.
You can't get a "caffeine prescription" yet, but its benefits in everyday life have been proven.
Conclusion
Coffee is better than its reputation. It does not cause high blood pressure, nor does it trigger cardiac arrhythmia when consumed in moderation. On the contrary, when consumed in moderate amounts, coffee is more beneficial than harmful to the heart. Only extremely high consumption poses a risk of caffeine overdose—normal coffee consumption is safe.
