Doctors have raised concerns about the cardiovascular risks associated with excessive energy drink consumption, following a case detailed in BMJ Case Reports. The report discusses a man in his 50s who suffered a stroke after regularly consuming eight cans of energy drinks per day, resulting in extremely high blood pressure.
The man experienced a stroke affecting his thalamus, which led to symptoms such as weakness and numbness on his left side, as well as difficulties with balance, walking, swallowing, and speech. Upon admission to the hospital, his blood pressure measured 254/150 mm Hg—levels considered dangerously high. Medical staff began treatment to lower his blood pressure, initially reducing it to 170 mm Hg.
Despite these interventions, the man's blood pressure remained elevated at home. Further investigation revealed he was ingesting approximately 1200-1300 mg of caffeine daily from energy drinks alone—well above the recommended maximum intake of 400 mg per day. After discontinuing energy drink use at doctors' advice, his blood pressure returned to normal and medication was no longer required. However, some neurological effects persisted.
Reflecting on his experience, the patient stated: "I obviously wasn't aware of the dangers drinking energy drinks were causing to myself. (I) have been left with numbness (in my) left hand side hand and fingers, foot and toes even after 8 years."
The authors noted that many people may not be aware of the potential cardiovascular risks linked to heavy energy drink consumption. They wrote: "The year 2018 saw major UK supermarkets implement a voluntary ban on sales of [these 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 ischaemic [restricted blood supply or blood clot] and hemorrhagic [bleed in the brain] strokes, particularly in younger demographics otherwise expected to have lower stroke risk."
Energy drinks typically contain more than 150 mg of caffeine per litre along with high levels of sugar and other chemicals. The report also points out that ingredients like guarana can add additional 'hidden caffeine.' According to the authors: "This declared amount is the 'pure caffeine', but other ingredients contain 'hidden caffeine'- for example, guarana is thought to contain caffeine at twice the concentration of a coffee bean."
They further explain: "The hypothesis is that the interaction of these other ingredients, including taurine, guarana, ginseng and glucuronolactone potentiates the effects of caffeine heightening stroke [cardiovascular disease] risk through numerous mechanisms."
On typical content levels they write: "The average [energy drink] is said to contain around 80 mg of caffeine per 250 ml serving compared with 30 mg in tea and 90 mg in coffee but in some cases can contain up to 500 mg in a single serving."
Although this case represents only one individual instance without conclusive evidence establishing causality across broader populations so far identified by research literature reviewed by BMJ Case Reports—the authors suggest regulatory changes could benefit public health outcomes: "While the current evidence is not conclusive given accumulating literature; high morbidity/mortality associated with stroke/[cardiovascular disease], well-documented adverse health effects from high-sugar drinks—we propose increased regulation over [energy drink] sales/advertising campaigns (often targeted at younger ages) could be beneficial for future cerebrovascular/cardiovascular health within our society."
