• Posted December 10, 2025

Do Energy Drinks Increase Stroke Risk? One Patient's Story

Energy drinks might give you wings, unleash the beast or fuel your grind — but chugging too many might pose a serious stroke risk, doctors warn.

An otherwise fit and healthy man in his 50s with a daily eight-can habit found out the hard way, according to a case study published Dec. 9 in the journal BMJ Case Reports. 

This patient suffered permanent damage from a minor stroke caused by extremely high blood pressure, doctors reported. His blood pressure returned to normal only after he quit energy drinks.

“I obviously wasn’t aware of the dangers drinking energy drinks were causing to myself,” said the patient, who was treated at Nottingham University Hospitals NHS Trust in the U.K. “(I) have been left with numbness (in my) left-hand side hand and fingers, foot and toes even after eight years.”

The man landed in the hospital after he experienced sudden left-side weakness, numbness and difficulties with balance, walking, swallowing and speech, according to the case report.

His blood pressure was clocked at 254/150 mm/Hg upon admission. Healthy blood pressure is considered 120/80 or lower.

Brain scans revealed he had suffered a stroke in his thalamus, the part of the brain involved in sensory perception and movement, doctors said.

The patient was started on drugs to lower his blood pressure, and his systolic pressure fell to 170 mm/Hg. Systolic is the top number of a blood pressure reading, and is the pressure within blood vessels during a heartbeat.

But once back home, the man’s blood pressure rose again even as doctors ramped up his blood pressure medications.

After some questioning, the man revealed he drank an average of eight energy drinks a day.

Each drink contained 160 mg of caffeine, adding up to a daily intake of 1,200 to 1,300 mg of caffeine, doctors said. The recommended maximum daily intake for caffeine is 400 mg.

Doctors insisted he quit energy drinks. When he did, his blood pressure returned to normal and he was able to go off his prescribed meds.

Few people see the potential harm in energy drinks, doctors wrote in their case report.

“The year 2018 saw major U.K. supermarkets implement a voluntary ban on sales of energy drinks to under-16s in a drive to tackle obesity, diabetes and tooth decay, but less explored are the possible increased risks of energy drinks for cardiovascular disease, including ischemic and hemorrhagic strokes,” wrote the team led by Dr. Martha Coyle of Nottingham University Hospitals.

Energy drinks boast high caffeine levels, “but other ingredients contain ‘hidden caffeine,’ ” the case report says. “For example, guarana is thought to contain caffeine at twice the concentration of a coffee bean.”

The interaction of caffeine and other ingredients — taurine, guarana, ginseng, glucuronolactone and sugar — can have a dramatic effect on blood pressure, increasing stroke risk, the team wrote.

“In patients with unexplained hypertension, clinicians should inquire about consumption of energy drinks,” the doctors wrote. “Lifestyle counseling should include a discussion about cardiovascular risk factors of energy drinks.”

The doctors did note that their report represents only one person, but argued that their concern is rooted in sound medicine.

“While the current evidence is not conclusive, given the accumulating literature, the high morbidity and mortality associated with stroke and cardiovascular disease and the well-documented adverse health effects of high-sugar drinks, we propose that increased regulation of energy drink sales and advertising campaigns (which are often targeted at younger ages) could be beneficial to the future cerebrovascular and cardiovascular health of our society,” the doctors concluded.

More information

Harvard Medical School has more on the health effects of energy drinks.

SOURCES: BMJ, news release, Dec. 9, 2025; BMJ Case Reports, Dec. 9, 2025