Study Links Energy Drinks and Stimulant Supplements to Higher Rates of Cardiac Events in Young Adults

A retrospective analysis of more than 28,000 FDA reports on cardiovascular events found that cardiac arrest, heart attacks and abnormal heart rhythms were reported far more often when the incidents involved caffeine-containing energy drinks or stimulant supplements. Cardiac arrest appeared about 11 times as frequently, heart attacks about 4.5 times, and ventricular arrhythmias or palpitations roughly four times as often compared with reports that did not involve these ingredients, according to the American Heart Association (AHA).

The study, to be presented at the AHA Scientific Sessions in Chicago in November 2026, noted that approximately 45% of the stimulant-related events involved adults aged 18 to 34. Products examined included soft drinks, meal-replacement shakes, protein bars, smoothies and vitamins that contain caffeine, guarana, yerba mate, synephrine, yohimbine and related compounds.

"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 Dr. Colin Kane, pediatric cardiologist at Children’s Health and professor at UT Southwestern Medical Center.

"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," noted Dr. Pamela Benavidez, cardiothoracic anesthesiologist at Fairfield Medical Center. "This means one small serving can easily surpass the advised daily limit or more."

The AHA’s 2026 scientific statement on caffeine advises that most adults can safely consume up to 400 mg of caffeine per day – roughly five 8-ounce cups of coffee – but many energy drinks and pre-workout products exceed that amount in a single serving. Benavidez warned that additional stimulants such as synephrine and yohimbine may interact with caffeine in ways that are not fully understood, especially in young, healthy individuals.

Researchers recommend that consumers monitor for symptoms such as palpitations, chest pain, lightheadedness, fainting or irregular heartbeat during or after use, and seek medical attention if they occur. They also advise people with known heart conditions, a family history of sudden cardiac events, or who take stimulant-affecting medications to consult a doctor before using these products.

The authors acknowledge limitations: the data are based on voluntary FDA reports, which may be incomplete or selective, and the observational design can only show association, not causation. Kane added that other factors – including alcohol, drug use, intense exercise or undiagnosed heart disease – could also contribute to the reported events.

Industry representatives responded that energy drinks have been consumed worldwide for decades and are considered safe by regulatory agencies when intake stays within the 400 mg caffeine guideline. Andrea Wong, chief science officer of the Council for Responsible Nutrition, said the analysis does not account for actual consumption patterns or dosage, making it impossible to determine the true incidence or risk level.

The study’s findings highlight the need for clearer labeling and consumer awareness about the caffeine and stimulant content of popular beverages and supplements.