How Energy Drinks Can Lead to Stroke

It seems innocent enough to sip on an energy drink when you’re feeling wiped. But a surprising new case study just linked the common habit to stroke.

There’s a major caveat of this BMJ Case Reports paper to point out upfront—namely that the patient regularly tossed back eight energy drinks a day. Still, it probably didn’t occur to him that this habit could give him a stroke.

But the findings are raising all kinds of questions about the link between energy drinks and stroke, and if your health might be at risk if you sip one of these a day. With that in mind, we tapped a neurologist, cardiologist, and toxicologist to break down how energy drinks can lead to a stroke, plus the safest way to approach these drinks going forward.

The case report starts out as a medical mystery.

As the report explains, the patient was a “normally fit and well” man in his 50s who went to the hospital after developing weakness on his left side, numbness, and clumsiness. An MRI confirmed that he suffered an ischemic stroke, which happens when a blood clot blocks an artery that supplies oxygen and nutrients to the brain.

His blood pressure was sky-high when he was admitted—254/150 mm Hg. Normal blood pressure is considered less than 120/80 mm Hg; anything higher than 180/120 mm Hg is a hypertensive emergency, according to the American Heart Association (AHA), and he was well above that.

The man spent 72 hours in the hospital, where doctors were able to get his blood pressure down. But after he was released, his blood pressure shot back up and stayed high, even after doctors put him on five different medications. It wasn’t until the man was questioned about his diet that doctors discovered that he regularly drank eight cans of energy drinks, which contained 160 milligrams of caffeine each. Once he stopped having those drinks, his blood pressure normalized and he was able to get off the medications.

The case report co-authors stressed that the findings raise the need for greater public awareness that you can, in fact, have a stroke from energy drinks.

How can energy drinks lead to a stroke?

The caffeine in these drinks is definitely a factor, Carolyn A. Cronin, MD, PhD, division chief of vascular neurology at Vanderbilt University Medical Center, tells SELF. “Energy drinks contain high doses of caffeine, and sometimes other agents [like taurine] as well, that can increase blood pressure,” she explains. “Elevated blood pressure causes damage to blood vessels throughout the body, but the brain is particularly susceptible.”