Energy drinks and supplements containing stimulants were associated with reports of serious heart problems, including cardiac arrest and heart attacks, in a new observational analysis focused on reports submitted to the Food and Drug Administration.

The research, released by the American Heart Association, is scheduled for presentation at the AHA Scientific Sessions in Chicago from November 6 to 9, 2026. The findings are preliminary and have not been published as a full peer reviewed manuscript.

Researchers conducted a retrospective analysis of more than 28,000 reports involving cardiovascular events. Those events included cardiac arrest, myocardial infarction, ventricular arrhythmias, palpitations, tachycardia, chest pain and syncope.

Cardiac arrest appeared in reports involving products with caffeine and stimulants about 11 times as often as in reports involving products without those ingredients. Heart attacks were reported about 4.5 times as often.

Reports of ventricular arrhythmias or palpitations appeared about four times as often among products containing the substances, according to the AHA. Elevated heart rate, chest pain and fainting also increased among the group consuming them.

Approximately 45% of reported cardiovascular events associated with stimulant products involved adults ages 18 to 34. The stimulants studied included caffeine, methylxanthines, guarana, yerba mate, synephrine, yohimbine and other compounds.

The substances were consumed through products such as soft drinks, meal replacement shakes, protein bars, smoothies and vitamins. That broad range means the analysis was not limited to products explicitly marketed as energy drinks.

Colin Kane, M.D., a pediatric cardiologist and service chief at Children's Health and professor at UT Southwestern Medical Center, was not involved in the research. He said the findings added to previous case reports about potential heart dangers from consuming high amounts of caffeine.

“We've known through case reports and anecdotal evidence that caffeine in high amounts can be potentially dangerous to people with underlying heart conditions and even those who have normal hearts,” Kane told Fox News Digital.

Adults can generally safely consume up to 400 mg of caffeine daily, according to a 2026 American Heart Association Scientific Statement on caffeine and cardiovascular disease. That amount is equivalent to as many as five 8 ounce cups of regular black caffeinated coffee.

Senior study author Dr. Pamela Benavidez, a cardiothoracic anesthesiologist at Fairfield Medical Center in Lancaster, Ohio, highlighted the caffeine concentrations found in some products. “Some energy drinks have up to three times more caffeine per fluid ounce than brewed coffee, and some pre-workout supplements have more than 12 times as much,” she told Fox News Digital.

“This means one small serving can easily surpass the advised daily limit or more.” Benavidez also noted that some products include additional stimulants such as synephrine, yohimbine and methylhexanamine.

“These can interact with caffeine in ways that are not fully understood, especially in young, healthy people,” she said. Researchers advised young people to monitor caffeine consumption and watch for palpitations, chest pain or tightness, lightheadedness, fainting, or a racing or irregular heartbeat.

“If you notice any of these symptoms, seek medical help right away,” Benavidez advised. She also urged people with a known heart condition, a family history of sudden cardiac events, or medications that act as stimulants or affect heart rate or rhythm to consult a doctor before using the products.

Kane said people with underlying heart conditions, particularly dangerous heart rhythms, and older adults with coronary artery disease should be especially aware. “And there's a whole group of people who may have an underlying heart condition that they're not diagnosed with yet,” he added.

The study cannot prove that the products caused the reported cardiac events because it was observational. The voluntary FDA reports may also contain incomplete, inconsistent or selectively submitted information, while factors including alcohol, drug use, strenuous exercise and undiagnosed heart conditions could have contributed.

“We don't know how many people consumed these drinks and didn't report symptoms or those who maybe had symptoms and didn’t report them,” Kane said. He also cautioned, “Anytime you're mixing stimulants and other substances or medications, it can certainly bring up a potential for harm.”

The American Beverage Association said moderate daily consumption of 400 milligrams of caffeine from all sources is considered safe for adults. It also said energy drinks contain less caffeine than coffeehouse coffee and that regulators have not found harmful interactions between caffeine and their other ingredients.

Andrea Wong, chief science officer of the Council for Responsible Nutrition, said the analysis did not establish how many consumers used the products, whether they were misused, or how much caffeine they contained. “Importantly, the reported 11-fold difference in cardiac arrest reporting does not mean consumers are 11 times more likely to experience cardiac arrest.”