Atrial fibrillation is the most common rhythm disorder that affects one in three people during their lifetime. For a long time, it was believed that caffeine acts as a provocateur, causing chaotic atrial contractions. However, recent data force us to reconsider this dogma. The authors of the project from the University of California in San Francisco decided to test the myth in practice. They selected 200 patients who had recently undergone electrocardioversion (restoration of rhythm by electric discharge). Half of them were allowed to drink about one cup of coffee a day, while the other half were asked to completely eliminate any caffeinated foods. The results of the six-month trial surprised even the skeptics. In the group where people enjoyed their favorite drink, the rhythm failure returned to only 47% of the participants. But among those who courageously abstained, 64% relapsed. The analysis showed that coffee drinkers had a 39% lower risk of a repeat attack. Moreover, these patients were less likely to require hospitalization. It turns out that a moderate dose of caffeine can play a protective role, helping to keep the heart in the right rhythm for longer. Experts believe that the secret lies in blocking the receptors of adenosine, a substance that can shorten the cardiac cycle and cause malfunctions. In addition, coffee has anti-inflammatory properties, which also has a beneficial effect on blood vessels. There is also a simpler version.: People who indulge in a cup of coffee are often more physically active, which improves overall health. Those who added a lot of sugar or cream to the drink risked gaining weight, but the caffeine itself had nothing to do with it. It is important to understand that we are talking about one cup a day, not liters of strong drink. The authors warn that the data is relevant for moderate consumption. Excessive doses can still be dangerous. In addition, the experiment had its limitations. The patients knew which group they were in, which could affect their well-being (the placebo or nocebo effect). Also, not all participants from the abstinence group honestly followed the ban. Nevertheless, cardiologists come to the conclusion that if you like coffee and suffer from arrhythmia, one cup a day is likely to do more good than harm.