Heavy consumption of energy drinks may raise the risk of heart disease and pose a serious risk of stroke, doctors have warned.

Millions of people worldwide regularly drink the products, which are non-alcoholic and typically contain more than 150mg of caffeine per litre, very high glucose-based sugar content and varying quantities of other chemicals.

Doctors in Nottingham, England, sounded the alarm after an otherwise fit and healthy man in his 50s had a stroke and was left with permanent numbness in his hands and feet. On questioning, he said he drank an average of eight energy drinks a day.

The case, reported in the medical journal BMJ Case Reports , also prompted doctors to call for tighter regulation of sales and advertising of energy drinks.

On admission to hospital, the patient’s

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