Reality Check: Does Coffee Really Make Your Heart 'Flutter'?

Is coffee consumption really linked to cardiac arrhythmias? The authors of a new study found coffee may even lower the risk of it.

There is a common belief that caffeine increases the risk of cardiac arrhythmias or irregular heartbeat, which can feel like a fluttering or racing heart. However, evidence to support this idea is "poorly substantiated," the researchers of a new study, published Monday in JAMA Internal Medicine, said.

For their study, the researchers sought to determine whether habitual coffee drinking is really linked to the risk of arrhythmias. To do this, they analyzed the coffee consumption of 386,258 people and compared it with the rates of cardiac arrhythmia. The participants did not have a prior diagnosis of arrhythmia, and the coffee drinkers had a median consumption of two cups of coffee per day, while 22.1% did not drink the beverage.

Among the participants, 16,979 developed arrhythmia during the follow-up. But instead of finding that the coffee drinkers had higher risks of arrhythmia, coffee consumption even appeared to lower the risk.

"After adjustment for demographic characteristics, comorbid conditions, and lifestyle habits, each additional cup of habitual coffee consumed was associated with a 3% lower risk of incident arrhythmia," the researchers wrote.

The researchers also looked at the CYP1A2 gene, or the "coffee gene," CNN noted. They did this to see if the genetic variants that affect caffeine metabolism affect the relationship between coffee consumption and arrhythmia risk.

People with the functioning version of the gene can metabolize coffee normally, which means they can ingest it without developing much "ill effects," the outlet explained. But if it is mutated, the body's rate of metabolizing coffee may be slower.

However, the researchers did not find an association between "genetically mediated differences in caffeine metabolism" and the heightened risk of cardiac arrhythmias.

"In this prospective cohort study, greater amounts of habitual coffee consumption were inversely associated with a lower risk of arrhythmia, with no evidence that genetically mediated caffeine metabolism affected that association," the researchers wrote. "Mendelian randomization failed to provide evidence that caffeine consumption was associated with arrhythmias."

The researchers noted the idea that causes heart palpitations came from "older, smaller" studies, CNN reported. They further noted 201 meta-analyses that found how moderate coffee consumption may be more "beneficial than harmful" to health.

Other possible benefits of consuming coffee include increasing one's energy levels, boosting metabolic rate, and lowering the risk of Parkinson's and Alzheimer's disease.