Energy drinks and other products containing stimulants may be associated with serious heart-related events, including cardiac arrest and heart attacks, with young adults making up a notable share of reports, according to preliminary research from the American Heart Association.
The analysis examined more than 28,000 reports submitted to the U.S. Food and Drug Administration involving cardiovascular events. These included cardiac arrest, heart attack, abnormal heart rhythms, palpitations, rapid heartbeat, chest pain and fainting. The findings are being presented at the AHA Scientific Sessions in Chicago, held November 6–9.
In reports involving products with caffeine or other stimulants, cardiac arrest was reported about 11 times as often as in reports involving products without those ingredients. Heart attacks appeared about 4.5 times as often, while abnormal heart rhythms or palpitations were roughly four times as common. Reports of elevated heart rate, chest pain and fainting were also more frequent.
About 45% of the cardiovascular-event reports linked to stimulant products involved people ages 18 to 34.
The substances included caffeine, methylxanthines, guarana, yerba mate, synephrine and yohimbine, among others. They can be found in energy drinks and also in products such as soft drinks, meal-replacement shakes, protein bars, smoothies and vitamins.
Colin Kane, a pediatric cardiologist and service chief at Children’s Health and professor at UT Southwestern Medical Center, said the results add to earlier case reports suggesting that high caffeine intake could pose risks to the heart.
“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,” said Kane, who was not involved in the research.
Adults can generally consume up to 400 milligrams of caffeine a day, equivalent to about five 8-ounce cups of regular black coffee, according to a 2026 AHA scientific statement on caffeine and cardiovascular disease.
But the amount in some products can be much higher. Senior study author Dr. Pamela Benavidez, a cardiothoracic anesthesiologist at Fairfield Medical Center in Lancaster, Ohio, said some energy drinks contain up to three times more caffeine per fluid ounce than brewed coffee. Some pre-workout supplements, she said, contain more than 12 times as much.
“This means one small serving can easily surpass the advised daily limit or more,” Benavidez said.
She also noted that these products may contain additional stimulants, including synephrine, yohimbine and methylhexanamine. “These can interact with caffeine in ways that are not fully understood, especially in young, healthy people,” she said.
The researchers advise young people to keep track of their caffeine intake and pay attention to symptoms such as palpitations, chest pain or tightness, lightheadedness, fainting, or a racing or irregular heartbeat during or after using these products.
“If you notice any of these symptoms, seek medical help right away,” Benavidez said. She added that people with a known heart condition, a family history of sudden cardiac events, or medications that are stimulants or affect heart rate or rhythm should speak with a doctor before using these products.
Kane said people with existing heart conditions may need to be especially cautious, including those with potentially dangerous heart rhythms and older adults with coronary artery disease. Some people, he added, may have a heart condition that has not yet been diagnosed.
The findings are preliminary and have not been published as a full peer-reviewed paper. Because the study was observational, it can show an association but cannot establish that the products caused the reported events.
“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. FDA reports are voluntary, so the data may also be incomplete or inconsistent, or reflect selective reporting.
Other factors could have played a role, including alcohol or drug use, strenuous exercise and undiagnosed heart conditions. “Anytime you’re mixing stimulants and other substances or medications, it can certainly bring up a potential for harm,” Kane said.
The American Beverage Association said energy drinks have been consumed around the world for more than 30 years and are considered safe by government food-safety agencies. It pointed to the FDA, Health Canada and the European Food Safety Authority, saying they rely on scientific evidence supporting moderate daily caffeine intake of up to 400 milligrams for adults.
The association also said energy drinks contain less caffeine than coffeehouse coffee and that no regulatory agency has found their other ingredients interact harmfully with caffeine.
Andrea Wong, chief science officer of the Council for Responsible Nutrition, said the analysis did not account for how many people used the products, whether they were misused or overused, or how much caffeine and other ingredients each serving contained. As a result, she said, it cannot establish the rate of cardiovascular events or quantify the risk.
“Importantly, the reported 11-fold difference in cardiac arrest reporting does not mean consumers are 11 times more likely to experience cardiac arrest,” Wong said.
