If you have a heart rhythm problem, the research so far calls for caution, but it does not settle the question for everyone. The clearest study is a 2024 report in Heart Rhythm on sudden cardiac arrest survivors with genetic heart disease, where 7 of 144 had consumed one or more energy drinks close to their event. That study covered only that group, so it does not directly address other arrhythmias or a family history of sudden cardiac death on its own.
What did the 2024 study find about energy drinks and arrhythmia?
Mayo Clinic researchers examined 144 sudden cardiac arrest survivors who had genetic heart disease. Seven of them (5%) had consumed one or more energy drinks in close proximity to their cardiac event, according to the 2024 Heart Rhythm study. The Elsevier press release announcing it, dated June 6, 2024, says the study did not prove direct causation.
The lead investigator, Michael J. Ackerman of Mayo Clinic, said other triggers were present in these cases, including sleep deprivation, dehydration, dieting or extreme fasting, and some QT-prolonging drugs. He called the relative risk small and the absolute risk of sudden death after an energy drink even smaller. He advised that patients with a known sudden death predisposing genetic heart disease should weigh the risks and benefits of such drinks.
| Source | What it looked at | What it found |
|---|---|---|
| 2024 Heart Rhythm study (Mayo Clinic) | 144 sudden cardiac arrest survivors with genetic heart disease | 7 (5%) had consumed one or more energy drinks close to the event; no direct causation proven |
| 2017 Cureus review (Mangi et al.) | Case reports, observational studies and meta-analyses | Describes cardiac arrhythmias, prolonged QT interval, myocardial infarction and death reported with energy drinks; calls for well-designed prospective studies |
| ClinicalTrials.gov registration NCT04149717 | Planned study of 35 men and women aged 18 to 39 | Registered with status UNKNOWN; a registration describes a study, not a result |
Why could an energy drink affect heart rhythm?
Energy drinks combine caffeine with other stimulants. The 2024 press release says researchers have postulated that these ingredients alter heart rate, blood pressure, cardiac contractility and cardiac repolarization in a potentially pro-arrhythmic manner. The 2017 Cureus review says that in an overdose, tachycardia followed by arrhythmias and hypotension can occur.
Manhattan Cardiology's patient page describes the same mechanism in plain terms: “This abrupt increase might cause palpitations or irregular heartbeats, which can be harmful for those with preexisting cardiac issues.” The National Heart, Lung, and Blood Institute defines arrhythmias as problems with the rate or rhythm of the heartbeat, which is what you would be watching for.
What do case reports say about people with heart problems?
The 2017 Cureus review collects case reports of young people whose heart rhythm problems followed energy drinks. These are individual cases, not controlled comparisons, and the review notes that some involved underlying structural heart disease, inherited cardiac problems, or other substances.
| Person in the case report | Heart history | Outcome described |
|---|---|---|
| Young woman | History of mitral valve prolapse; drink contained guarana, ginseng and caffeine | Ventricular fibrillation and death |
| Young woman | Confirmed type 1 long QT syndrome by genetic testing | Cardiac arrest within four hours after ingesting an energy drink |
| Adolescent woman | Long QT syndrome confirmed by genetic testing | Chest pain and palpitations after drinking energy drinks every other day for two weeks |
| Young adult male | Brugada syndrome pattern found after resuscitation | Ventricular fibrillation after drinking energy drinks with alcohol |
| Patient with tetralogy of Fallot | Structural heart disease | Ventricular tachycardia after consuming energy drinks |
How much caffeine is too much if you have a heart condition?
The 2024 press release says energy drinks contain 80 to 300 mg of caffeine per serving, compared with 100 mg in an 8-ounce cup of brewed coffee. A 200 mg drink falls inside that range, and 300 mg is at the top of it.
| Drink | Caffeine per serving |
|---|---|
| Energy drink (range reported by Mayo Clinic researchers) | 80 to 300 mg |
| 8-ounce cup of brewed coffee | 100 mg |
The research does not give an age-based or heart-based caffeine limit. For your own limit, and for a 16-year-old, ask a cardiologist or pediatrician what amount fits the heart history involved. Check the label for the exact caffeine in your can, since products differ.
Can energy drinks cause a heart attack?
The 2017 Cureus review describes case reports of myocardial ischemia and infarction after energy drink use, and calls this an association. One case describes a young man who had a cardiac arrest seven hours after drinking seven to eight cans. Another describes a young male with crushing chest pain after drinking 20 cans, and the published report of that 20-can case also involved ecstasy.
These cases involved large amounts and do not show what a single can does. The review concludes that well-designed prospective studies are needed to prove the link between energy drinks and cardiovascular events.
What is not known yet?
It is not established that energy drinks cause life-threatening arrhythmias. Peter J. Schwartz, co-author of an editorial accompanying the 2024 study, said there is “no clear and definitive evidence” of that and that more data are necessary.
The 2024 study covered sudden cardiac arrest survivors with genetic heart disease. It did not address people with other arrhythmias or a family history of sudden cardiac death alone.
A registered study, ClinicalTrials.gov registration NCT04149717, plans to test whether caffeine alone, or caffeine with taurine and L-carnitine, changes cardiovascular function in adults aged 18 to 39. Its status is listed as UNKNOWN, so no results are available yet.
In the June 2024 press release, Dr. Ackerman said energy drinks are not regulated by the US Food and Drug Administration. The 2017 Cureus review describes the FDA's role in regulating energy drinks as limited. Under the Dietary Supplement Health and Education Act of 1994, supplement ingredients do not require FDA approval, and energy shots are labeled as dietary supplements.
Which energy drink is safest, or which is worst for your heart?
The research discussed here compares drinks by caffeine and other stimulants, not by brand, so no brand is named as safest. Manhattan Cardiology's patient page recommends water, herbal teas and natural fruit juices as better options that provide energy without putting your heart at risk.
Read the label for caffeine per serving and for the other stimulants the review lists as common ingredients: taurine, guarana and ginseng. If you also take a pre-workout, the stacking question is covered in pre-workout safety, and heart safety and performance supplements covers stimulants more broadly.
Before you drink an energy drink again
- Ask your cardiologist whether energy drinks fit your heart history, and if so, what caffeine amount is right for you.
- Read the label for caffeine per serving and for taurine, guarana and other stimulants.
- Note when you drink one and any symptoms that follow, and bring that record to your appointment.
- If you feel chest pain, fainting or a racing or irregular heartbeat after a drink, call emergency services right away.
By the Gym Floor Guide Editorial Team
This article is for general information purposes only and does not constitute medical advice. Consult your doctor or qualified healthcare provider before making changes to your health routine.