Caffeinated energy drinks and stimulant supplements appear far more often than expected in federal reports of heart attacks and cardiac arrest among young adults, according to research presented at the American Heart Association's Scientific Sessions 2026 in Chicago.
What the analysis found
The study, abstract MDP0323, examined reports submitted to the Food and Drug Administration about adverse events tied to caffeine and stimulant products. Reports involving energy drinks or supplements were about 4.5 times more likely to mention a heart attack and four times more likely to mention ventricular arrhythmias or palpitations.
The pattern was strongest among adults aged 18 to 34, the group that consumes the most of these products.
Causation is still unproven
The findings are preliminary and have not been peer reviewed. Report databases record what consumers and clinicians submit, not verified diagnoses, and they cannot show that a drink caused an event.
This study raises concerns that products with very high amounts of caffeine may be harmful to the cardiovascular system, said Gregory Marcus of the University of California, San Francisco, who chairs the association's 2026 statement on caffeine and cardiovascular disease. He added that other factors may have influenced the results.
Brian Downey, director of general cardiology at Tufts Medical Center, told a Boston television station that the gap was quite a bit higher than we would expect to see.
What doctors suggest
Cardiologists say people with arrhythmias, high blood pressure, anxiety or sleep problems should be careful with high-dose caffeine. Mixing energy drinks with alcohol or heavy exercise raises risk further.
The United States does not cap caffeine in energy drinks, though several countries require warning labels and some restrict sales to minors. The study adds pressure for labeling rules, and it gives clinicians a concrete question to ask younger patients who arrive with palpitations.
Sales of the products keep climbing, especially among teenagers and college students, which is why cardiologists say the question matters more now than it did a decade ago.