Energy drinks and stimulant supplements are raising new concerns about heart health after researchers discovered a striking pattern in reports of serious cardiovascular emergencies. Products containing caffeine and other stimulants appeared far more frequently in reports of cardiac arrest, heart attacks, and other heart problems than products without these ingredients.
The findings were particularly concerning among younger adults. People ages 18 to 34 accounted for a substantial share of the reported heart problems involving caffeinated products, according to independent, preliminary research presented at the American Heart Association’s Scientific Sessions 2026.
Researchers emphasized that the findings do not establish that energy drinks or stimulant supplements caused these medical emergencies. However, the unusually high frequency of certain cardiovascular events in FDA safety reports suggests that these widely available products deserve closer examination.
Growing Concerns About Energy Drinks and Heart Health
The energy drink industry has expanded rapidly, with sales more than doubling over the past decade and exceeding $20 billion in 2024. Despite their popularity, scientists still have limited information about the cardiovascular effects of energy drinks and supplements containing stimulants.
Existing evidence suggests that consuming large amounts of caffeine can harm the cardiovascular system. Medical professionals have also documented cases of arrhythmias (irregular heart rhythms) and sudden cardiac death following the consumption of these products. Some of these incidents involved young adults who had no previously identified risk factors for heart disease.
A 2026 American Heart Association Scientific Statement on caffeine and cardiovascular disease indicates that most adults can generally consume up to 400 mg of caffeine daily without significant safety concerns (the equivalent of up to 5, 8-ounce cups of regular black caffeinated coffee).
However, caffeine concentrations can differ dramatically between products. Certain energy drinks provide up to three times as much caffeine per fluid ounce as brewed coffee, while some pre-workout supplements contain more than 12 times the concentration found in coffee.
Another concern involves how these products are regulated. The U.S. Food and Drug Administration (FDA) classifies energy drinks and stimulant supplements as foods or dietary supplements rather than medications. As a result, they are not subject to the same safety testing requirements that medications must meet before entering the market.
“These products are marketed as everyday pick-me-ups and sold next to soda and bottled water, so most people assume they carry no real risk,” said study author Sai Samayamanthula, a fourth-year medical student at the University of Virginia School of Medicine in Charlottesville, Virginia. “For many healthy people, if these products are consumed occasionally, the risk is probably small. However, individuals who consume energy drinks or other stimulant-containing supplements regularly can quickly exceed the recommended daily limit for caffeine, so it’s important for people to know that there may be a risk of cardiovascular harm with these products.”
FDA Reports Reveal Striking Differences in Cardiac Events
To investigate possible cardiovascular safety concerns, researchers examined a federal database containing reports of suspected adverse reactions to foods and dietary supplements. They compared products containing caffeine and other stimulants with products that did not contain these ingredients.
The comparison group included commonly consumed products such as soft drinks, smoothies, vitamins, protein bars, and meal replacement shakes. Researchers examined reports involving people ages 13 and older submitted between 2017 and 2025.
Several differences stood out in the analysis:
- Cardiac arrest: Reports involving caffeine and stimulant products were approximately 11 times more likely to mention cardiac arrest than reports involving products without these ingredients.
- Heart attacks: Heart attacks appeared about 4.5 times more frequently in reports associated with energy drinks and stimulant supplements.
- Abnormal heart rhythms: Reports involving stimulant products were roughly four times more likely to include ventricular arrhythmias (abnormal rhythm in the heart’s lower pumping chambers) or heart palpitations.
- Other cardiovascular symptoms: The researchers also identified higher reporting frequencies for rapid heart rate (nearly 3 times more often), chest pain (2.71 times more often) and fainting (about 2 times more often).
- Young adults: Approximately 45% of cardiovascular event reports involving caffeine and stimulant products concerned adults between ages 18 and 34.
- Men and women: Comparable patterns appeared in reports submitted for both sexes.
These differences describe how frequently certain medical problems appeared within the FDA reports. They do not mean that people consuming energy drinks face an 11 times greater actual risk of cardiac arrest or a 4.5 times greater risk of having a heart attack.
“Our findings support the case for more systematic safety monitoring of caffeine- and stimulant-containing products. In addition, healthcare professionals should remember to ask their younger patients who have palpitations, chest pain, or fainting spells if they recently or regularly consume these products,” Samayamanthula said.
Why Young Adults May Be Particularly Vulnerable
One of the most notable findings was the large proportion of cardiovascular reports involving younger adults. Researchers have not yet determined why the connection between stimulant products and reported heart problems appeared so frequently in this age group.
Several explanations are possible. Younger consumers may use energy drinks and stimulant supplements more often, increasing the likelihood that these products appear in reports of medical emergencies.
How the products are consumed could also influence the pattern. Potential contributing factors include the circumstances surrounding their use (for example, consuming them before intense exercise or mixing them with alcohol or drugs). Some individuals may also have previously undiagnosed heart conditions that could make them more susceptible to cardiovascular complications.
These possibilities remain uncertain, and additional research will be needed to determine which factors, if any, help explain the unusually high reporting frequency among younger adults.
Do Energy Drinks Actually Cause Heart Attacks?
Although the results raise important questions about products containing concentrated caffeine and other stimulants, experts caution against interpreting the findings as proof of a direct cause.
“This study raises concerns that products with very high amounts of caffeine may be harmful to the cardiovascular system,” said Gregory M. Marcus, M.D., M.A.S., FAHA, chair of the 2026 American Heart Association scientific statement on caffeine and cardiovascular disease. “Although there are biological reasons why that connection could be possible, the study does not prove that caffeine products cause these events, because other factors may have influenced the results found in this analysis. More research is needed to understand whether these stimulant products are truly responsible for the reported heart-related events.”
Marcus did not participate in the research. He is a professor of medicine at the University of California, San Francisco School of Medicine and serves as associate chief of the Cardiology for Research program at the University of California, San Francisco Health.
Because the analysis relied on reports submitted voluntarily to the FDA, it cannot establish whether the products themselves were responsible for the cardiovascular events. Other health conditions, behaviors, or circumstances may have played a role.
How Researchers Analyzed the FDA Safety Reports
The research team reviewed 28,345 reports of possible adverse events submitted to an FDA safety database from 2017 through 2025.
Of these, 854 reports involved energy drinks or dietary supplements containing caffeine or other stimulants. The remaining 27,491 reports concerned products without caffeine or stimulant ingredients and served as the comparison group.
Researchers classified products according to the ingredients they contained. The stimulant category included caffeine, methylxanthines (theobromine, guarana, yerba mate, green tea/coffee extracts) and sympathomimetics (synephrine, yohimbine, ephedra, DMAA, higenamine).
Rather than evaluating individual brands, the researchers grouped products by their ingredients. Consequently, the findings apply to broad categories of caffeinated and stimulant products and do not identify any particular brand as more dangerous than another.
The researchers also highlighted important limitations in the available data. Reports were voluntarily submitted by members of the public, consumers, healthcare professionals, and manufacturers, meaning that the database does not provide a complete record of everyone who experienced a possible adverse reaction.
Just as importantly, the researchers could not determine how many people consumed these products without developing cardiovascular problems. They also could not establish how many people experienced heart problems but never submitted a report.
Without those figures, the analysis cannot calculate the actual likelihood of a heart attack, cardiac arrest, or another cardiovascular event among consumers of energy drinks and stimulant supplements.
Nevertheless, the findings reveal a potentially important safety signal. Researchers say more systematic monitoring and further studies are needed to determine whether these products contribute directly to serious heart problems, particularly among younger adults who frequently consume them.
