Can energy drinks increase your risk of stroke?

A long drive. An afternoon slump. An upcoming exam that requires an all-nighter for prep. In situations like these, reaching for an energy drink—with its punch of caffeine and other vitality-boosting ingredients—often feels like a solution.

If you drink these beverages regularly, you’re far from alone—they're a popular choice, particularly with teens and young adults. It's important to know, however, that overuse of energy drinks can be accompanied by serious health implications, particularly to your heart and possibly to your brain.

Sure, a temporary energy boost may be tempting, says Jimmy John Novero, MD, a neurologist in Las Vegas. “But just like anything else that we eat or drink, our bodies are ultimately affected. And the effects at high doses may not always be good.”

Discover some of those health risks linked to consuming energy drinks—including a potential connection to strokes.

They pack a wallop

Energy drinks often tout that they’re made from all-natural ingredients. Scan the ingredient list and you may see caffeine, taurine (an amino acid), guarana and yerba mate (both plant-derived sources of caffeine), and B vitamins. But just because ingredients are claimed to be natural doesn’t mean they’re totally safe.

Take caffeine. A 16-ounce energy drink might contain anywhere from 70 to 240 milligrams of caffeine or even considerably more. Energy shots typically have between 113 and 200 mg. An 8-ounce cup of coffee, meanwhile, may contain between 80 and 100 mg of caffeine, while a similarly sized cup of green or black tea contains between 30 to 50 mg. A 12-ounce caffeinated soft drink has between 30 and 40 mg.

For reference, the U.S. Food and Drug Administration advises that up to 400 mg of caffeine per day is considered safe for most healthy adults. That means you’ll hit a reasonable daily limit after four or five cups of coffee—but you’ll get there after as few as two or even one high-octane energy drink.

Cardiovascular concerns are real

All that “energy” packed into a slender can means you can enter questionable health territory quickly. “Energy drinks contain high amounts of caffeine that can affect our blood pressure, heart rhythms, and blood flow,” says Dr. Novero, particularly if you have cardiovascular issues to begin with.

The potential effects of those other ingredients—whether they augment the effects of caffeine or work on their own—are also concerning. Some studies suggest they may influence blood pressure and heart rate, which can be problematic, especially for people with certain long-term health issues.

“If you have a chronic health condition—such as diabetes, hypertension, or heart disease—energy drinks may result in increased risks,” Novero says.

The hazards from having too much energy drink over a short period of time may include rapid heartbeat (tachycardia) and irregular heartbeat (arrhythmia), according to the American College of Cardiology (ACC). Some case reports have also linked energy drinks to heart attack, cardiac arrest, and aortic dissection (which involves the tearing of the major blood vessel leading from the heart), though more studies are needed to prove a cause-and-effect relationship.

The picture associated with long-term, regular use isn’t much better, says the ACC, as potential effects include coronary artery disease, hardening of the arteries, and reduced blood flow throughout the body.

What about the risk of stroke?

Another potential side effect of having too many energy drinks is a condition known as reversible cerebral vasoconstriction syndrome (RCVS), which results from a sudden tightening of the vessels that supply blood to the brain. The hallmark symptom of RCVS is an acute, severe headache (often described as a “thunderclap” headache), Novero explains.

As its name implies, RCVS itself is reversible, and most patients who experience it make a full recovery. But in the worst-case scenario, RCVS may trigger a stroke, which can cause lasting damage, and even death.

The exact cause of RCVS is not known, and it tends to crop up suddenly and without warning. It’s not only linked to energy drinks but is also associated with the use of certain prescription drugs that narrow arteries in the brain (such as some antidepressants and migraine medications), over-the-counter decongestants, and nicotine patches, as well as marijuana and illegal drugs including cocaine, ecstasy, amphetamines, and LSD. It’s tied to certain types of tumors and pregnancy, too.

The vast majority of people who have these conditions or use these drugs or energy drinks will never experience RCVS, just as most healthy adults can safely consume an energy drink without suffering heart complications. But the large amounts of caffeine in many energy drinks is concerning to experts like Novero because it can lead to the constriction of blood vessels, and the long-term effects of regular consumption haven’t been fully studied.

Kids are at risk

The threat posed to kids is particularly worrisome, considering that anywhere from 30 to 50 percent of teenagers consume energy drinks on a regular basis and that manufacturers aggressively market the products toward this age group. The recommended daily caffeine limit for adults is 400 mg. But top health expert groups, including the American Academy of Pediatrics and American Heart Association, advise kids between ages 5 and 18 to avoid energy drinks entirely.

The National Center for Complementary and Integrative Health, a division of the National Institutes of Health, notes that “a growing body of scientific evidence shows that energy drinks can have serious health effects, particularly in children, teenagers, and young adults.”

And that’s not to mention several non-cardio adverse effects linked to energy drinks in adults and kids, such as anxiety, depressive symptoms, insomnia, psychosis, high-risk behavior, and acute kidney failure.

Think twice before reaching for an energy drink

Should you stop drinking energy drinks altogether? Novero recommends discussing your consumption with your healthcare provider, who can advise you about risks given your health status and any medications you’re taking. People who are especially sensitive to caffeine or who have underlying medical conditions should be particularly cautious, as should pregnant or breastfeeding women. Children should not have energy drinks.

“I would recommend that one should be very judicious and cautious in consuming energy drinks, just like when consuming other drinks or beverages such as wine, beer, or coffee,” Novero says. “As with so many substances, the amount you consume makes a big difference.”