Energy drinks and stimulant supplements linked to heart problems in young adults, study finds

Energy drinks and supplements containing caffeine and other stimulants have been linked to serious heart problems in new research, including cardiac arrest and heart attacks. Reports of such problems were more common among users of these products, and the risk was highlighted particularly among young adults.

The research, released by the American Heart Association (AHA), is being presented at the AHA Scientific Sessions in Chicago, held from November 6 to 9, 2026. The researchers analysed more than 28,000 reports of cardiovascular events submitted to the US Food and Drug Administration (FDA).

The analysis found that cardiac arrest appeared in reports involving caffeine- and stimulant-containing products about 11 times as often as in reports involving products without those ingredients. Heart attacks were reported about 4.5 times as often, while ventricular arrhythmias, or abnormal heart rhythms, and palpitations were reported about four times as often.

About 45 percent of the reported cardiovascular events associated with stimulant products involved adults aged 18 to 34. Elevated heart rate, chest pain and fainting were also reported more often among users of these substances.

The stimulants covered in the study included caffeine, methylxanthines, guarana, yerba mate, synephrine, yohimbine and other compounds. They were consumed in products such as soft drinks, meal replacement shakes, protein bars, smoothies and vitamins.

Dr Colin Kane, a paediatric cardiologist and professor at UT Southwestern Medical Center who was not involved in the study, said earlier case reports had already suggested that caffeine in high amounts can be potentially dangerous for people with underlying heart conditions, and even for those with normal hearts.

According to a 2026 American Heart Association scientific statement on caffeine and cardiovascular disease, it is generally safe for adults to consume up to 400 mg of caffeine per day, which is about five 8-ounce cups of regular black coffee. But some energy drinks contain up to three times more caffeine per fluid ounce than brewed coffee.

Dr Pamela Benavidez, a cardiothoracic anaesthesiologist at Fairfield Medical Center in Lancaster, Ohio, and senior author of the study, said some pre-workout supplements contain more than 12 times as much caffeine as coffee. In her words, one small serving can easily surpass the advised daily limit.

Benavidez also warned that these products often include other stimulants such as synephrine, yohimbine and methylhexanamine. She said these can interact with caffeine in ways that are not fully understood, especially in young, healthy people.

The researchers recommend that young people carefully monitor their caffeine consumption and watch for heart-related symptoms, such as palpitations, chest pain or tightness, lightheadedness, fainting, or a racing or irregular heartbeat during or after use of these products. Anyone noticing such symptoms should seek medical help right away, Benavidez advised.

She added that people with a known heart condition, a family history of sudden cardiac events, or who take medicines that can affect heart rate or rhythm should talk to a doctor before using these products at all.

The researchers also pointed to the limits of the study. It was observational, so it could only show an association and could not prove that the products caused the cardiac events. The findings are preliminary and have not yet been published as a full peer-reviewed manuscript.

In addition, the FDA reports were submitted voluntarily, so they may contain incomplete, inconsistent or selectively submitted data. It is not known how many people consumed these drinks and did not report symptoms, or had symptoms and did not report them. Other factors, such as alcohol or drug use, strenuous exercise and undiagnosed heart conditions, may also have contributed to the events.

The American Beverage Association, based in Washington, DC, said in a statement that energy drinks have been enjoyed by billions of people around the world for more than 30 years and are recognised as safe by government food safety agencies worldwide. It said the FDA, Health Canada and the European Food Safety Authority had all determined that a moderate daily intake of 400 milligrams of caffeine from all sources is safe for adults.

Andrea Wong, chief science officer of the Council for Responsible Nutrition in Washington, DC, said the analysis does not account for how many consumers actually used the products, whether they were overused or misused, or even the amount of caffeine per serving, so it cannot determine the incidence of cardiovascular events or quantify the associated risk. She said the reported 11-fold difference in cardiac arrest reporting does not mean consumers are 11 times more likely to experience cardiac arrest.