Study links energy drinks and stimulant supplements to higher rates of cardiac events
An American Heart Association analysis of FDA reports found that caffeine-containing energy drinks and pre-workout products were associated with a markedly higher frequency of cardiac arrest, heart attacks and arrhythmias, especially among adults aged 18 to 34.
An analysis of more than 28,000 FDA reports of cardiovascular events presented at the American Heart Association Scientific Sessions in Chicago found that cardiac arrest was reported about 11 times more often when caffeine- and stimulant-containing products were involved, and heart attacks occurred roughly 4.5 times as often, according to the association. The study, which examined reports of cardiac arrest, myocardial infarction, ventricular arrhythmias, palpitations, tachycardia, chest pain and fainting, indicated that roughly 45% of the events linked to stimulant products occurred in adults aged 18 to 34.
The stimulants identified included caffeine, methylxanthines, guarana, yerba mate, synephrine, yohimbine and related compounds, consumed in items such as soft drinks, meal-replacement shakes, protein bars, smoothies and vitamins. Senior study author Dr. Pamela Benavidez noted that some energy drinks contain up to three times more caffeine per fluid ounce than brewed coffee, and certain pre-workout supplements may exceed twelve times that amount, meaning a single serving can surpass the recommended 400 mg daily limit for adults.
"If you notice any of these symptoms, seek medical help right away," Benavidez advised. "If you have a known heart condition, a family history of sudden cardiac events, or take medications that affect heart rate or rhythm, you should talk to your doctor before using these products."
Pediatric cardiologist Dr. Colin Kane, who was not involved in the study, said the findings reinforce earlier case reports suggesting high caffeine intake can be dangerous for people with underlying heart conditions and may also affect individuals with otherwise normal hearts. He cautioned that mixing stimulants with alcohol, drugs or strenuous exercise could increase risk.
The researchers emphasized that the analysis is observational and cannot prove causation. They also highlighted limitations such as voluntary reporting to the FDA, which may lead to incomplete or selective data, and the inability to account for factors like alcohol use, other substances or undiagnosed heart disease.
The American Beverage Association responded that energy drinks have been consumed safely for decades and are considered safe by multiple 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 measure how many consumers use the products, the dosage per serving, or the incidence of events, and therefore cannot quantify the actual risk to individuals.