Coffee lovers enjoy sipping a hot cup of java first thing in the morning, but for some people, especially those with heart disease and high blood pressure, caffeine can cause problems. One fairly common irregular heart rhythm that occurs both in healthy people and people with heart disease is atrial fibrillation. Atrial fibrillation is a rhythm that can come and go, and many doctors think lifestyle factors such as smoking, lack of sleep, stress and drinking too much coffee bring it on in a susceptible person. Does caffeine cause atrial fibrillation?
Can Caffeine Be a Cause?
Some people with atrial fibrillation are convinced that caffeine makes their symptoms worse. On the other hand, research doesn’t support this. According to a study published in the American Journal of Clinical Nutrition and published on Medscape.com, caffeine doesn’t cause atrial fibrillation.
In this large study involving almost 48,000 middle-aged and older people, researchers compared the risk of atrial fibrillation to how much caffeine the participants took in daily. After following them for 5.5 years to see how many developed atrial fibrillation, they found no association between caffeine consumption and atrial fibrillation risk.
One flaw in the study was they didn’t have a group who consumed no caffeine. It’s possible that completely abstaining from caffeine could lower the risk of atrial fibrillation, but this would need to be researched. This study also only looked at consumption of caffeine from coffee - not tea, soft drinks or chocolate. It would be even more convincing to see no increase in atrial fibrillation risk from caffeine in any form. They did find that caffeine in coffee slightly increases blood pressure when five or more cups are consumed a day.
Even more interesting is a study published in the Journal of Electrocardiology, which not only didn’t find that caffeine causes atrial fibrillation, but when animals were given caffeine intravenously, it reduced their susceptibility to atrial fibrillation both in those that were healthy and animals predisposed to this irregular heart rhythm.
Caffeine, Atrial Fibrillation and Heart Health
Despite these results, most doctors are reluctant to advice patients with heart disease or atrial fibrillation to drink caffeinated beverages. Caffeine speeds up the heart rate and raises cortisol level, the so-called stress hormone, which can have negative effects on the heart.
The Bottom Line
Does caffeine cause atrial fibrillation? There’s no evidence that it does based on current research. Still the effects of caffeine weren’t examined under all conditions such as when a person is under stress. It’s possible that the combination of caffeine and physical or mental stress could bring on atrial fibrillation. For this reason, it’s best to consume caffeine in moderation if you’re at high risk for atrial fibrillation – to be safe.
J Electrocardiol. 2006 October; 39(4): 421–425.
Medscape.com. “Caffeine Not Associated with Increased Risk of Atrial Fibrillation”