Researchers in Australia say coffee, even in large amounts, doesn’t increase the frequency of cardiac arrhythmias. Other experts do have a few words of caution.
Are you drinking that third cup of coffee with a side of guilt?
You may be cheered by a recent study out of Australia that refutes the notion that coffee and tea increase the frequency of cardiac arrhythmias.
The study is detailed in a review published in JACC: Journal of the American College of Cardiology.
“There is a public perception, often based on anecdotal experience, that caffeine is a common acute trigger for heart rhythm problems,” said Peter Kistler, MBBS, PhD, a lead author of the review and director of electrophysiology at Alfred Hospital and Baker Heart and Diabetes Institute in Melbourne, Australia.
“Our extensive review of the medical literature suggests this is not the case,” he told Healthline.
Abnormal heart rhythms cause the heart to beat too quickly, too slowly, or unevenly.
While some arrhythmias may be harmless or even go unnoticed, others can increase risk for sudden cardiac arrest.
The most common heart rhythm disorder is atrial fibrillation (AFib), which causes the heart to beat rapidly and skip beats. Left untreated, it can cause strokes.
The authors analyzed multiple population-based studies to determine an association between caffeine intake and its effects on atrial (and ventricular) arrhythmias.
The researchers said these studies have consistently shown a decrease in AFib with an increase in caffeine ingestion, with one meta-analysis of 228,465 participants showing AFib frequency decreasing by 6 percent.
The authors determined that caffeine has no effect on ventricular arrhythmias (VAs). Consuming up to 500 mg daily (equivalent to six cups of coffee) did not increase the severity or rate of VAs.
A randomized study of 103 post-heart-attack patients who received an average of 353 mg/day resulted in improved heart rate and no significant arrhythmias.
Only two studies showed an increased risk for VAs, where patients ingested at least 10 cups and 9 cups per day, respectively.
Kistler, who drinks two or three cups of coffee a day, explained the origin of the study this way: “I see a lot of people who are told by their doctors to stop drinking coffee, which leaves them disappointed and usually doesn’t make a difference to their heart rhythm.”
“I suspected coffee was not associated with an increase in arrhythmias but had not appreciated that people who drink coffee regularly may actually have fewer arrhythmias,” he added.
Kistler concludes that two to four cups per day is good for the heart, with regular coffee drinkers having lower incidences of heart failure, coronary disease, and heart rhythm problems.
“There is no clear evidence that coffee is detrimental, although everyone is different and if people feel coffee exacerbates symptoms, then it is sensible to reduce or avoid it,” Kistler said.
Cardiologist Nieca Goldberg, who practices in New York, told Healthline that coffee is a stimulant that some people are sensitive to.
“Those with sensitivities may get palpitations,” she noted.
Generally, she takes a moderate position on the subject.
“Coffee is not as bad as its reputation suggests. There’s also caffeine in chocolate and in colas,” she said.
The solution is to consume these things in moderation and allow for individual body responses.
“People with heart attacks want their coffee,” Goldberg said. “But you don’t want to develop tachycardia [racing heart rate].”
It’s not just studies that reverberate in American kitchens. It’s also genetics.
There is similar advice in the kitchen.
According to Kristin Kirkpatrick, MS, RD, LD, a licensed, registered dietitian who is wellness manager at the Cleveland Clinic Wellness Institute, people should “listen to their body and recognize what you can and can’t tolerate.”
“I believe that there are always genetics that must be looked at when coffee consumption is considered,” she told Healthline.
“This study would not make me tell my heart patients (who choose to limit or avoid coffee) to increase their consumption, or my patients with genetic susceptibility to clear caffeine from the system slower than normal,” she explained. “I often say that, with caffeine, you have to listen to your body, and recognize what you can and can’t tolerate.”
“I see a lot of patients for the purpose of nutrigenomics testing, which has an area of the test that determines if they have certain gene types for the NYP1A2 gene that cause them to be ‘slow’ metabolizers of caffeine, which ultimately puts them more at risk for higher blood pressure and heart attack,” she added.
Self-diagnosis is easy.
“Do you feel jittery, racing heart, unable to sleep, etc. when you drink coffee? If so, listen to that and reduce to an amount that feels better,” Kirkpatrick said. “We need more studies like this to truly determine if coffee is a beneficial stimulant for heart patients.”
She added that measuring can be tricky. Mugs hold more than cups, for example.
“These days caffeine can be found in energy dinks, chocolate-covered espresso beans, and even some energy bars,” she said. “Having access to so many food choices may make it hard to track how much one is actually consuming.”
So instead of fretting about it, have that coffee with a calculator that lets you keep track of how much caffeine you’re consuming.
And, regardless of the numbers, quit if you don’t feel well.