A healthy man suffers a stroke and permanent damage after consuming numerous energy drinks

Energy drinks may contain high levels of caffeine, sugar and other ingredients which boost blood sugar. (SolStock/E+/Getty Images via CNN Newsource)

He was healthy and fit at 54, an avid runner with no vices — he didn’t smoke, drink or do drugs. So when he suddenly experienced left-sided weakness, numbness and difficulties with balance, walking, swallowing and speech, a family member rushed him to a nearby stroke clinic.

“His blood pressure was sky high — about 254 over 150 millimetres — yet when you looked at him you’ve never know it, because he looked so well. That’s why we call hypertension the silent killer,” said Dr. Sunil Munshi, a consulting physician at Nottingham University Hospitals NHS Trust in the United Kingdom.

Munshi is the senior author of a case report about the man, a warehouse worker from Sherwood, Nottingham, whose name was withheld to protect his privacy. The paper was published Tuesday in the journal BMJ Case Reports.

Normal blood pressure for adults is less than 120 over 80 mm HG (millimetres of mercury). Blood pressure of 180 over 120 or higher is considered a medical crisis that requires immediate emergency care.

“His left side was numb, and scans showed he had a stroke in the deeper part of the brain, the thalamus, which explains the unsteadiness,” Munshi said. “He was admitted, and we treated him with five different medications until his blood pressure dropped to 170.”

Back at home again, the man’s blood pressure continued to climb, reaching 220 despite numerous drugs. Munshi and his team searched for answers for weeks, running extensive tests that turned up negative. Then one day the man told Munshi about his energy drink habit.

“Each day he consumed eight highly potent energy drinks to stay alert for his job — two cans at four different times during the day,” Munshi said. (The brand name was withheld from the study.) “Each of the drinks contained 160 milligrams of caffeine. Suddenly the diagnosis was clear.”

Some energy drinks can have up to 500 milligrams of caffeine, compared with 30 milligrams in tea and 90 milligrams in coffee, said study first author Dr. Martha Coyle, a resident doctor at Nottingham University Hospitals NHS Trust.

“In the U.K., guidelines suggest 400 milligrams of caffeine a day, between two and four cups,” Coyle said. “This gentleman was consuming 1,200 to 1,300 milligrams, three times the amount.”

The U.S. Food and Drug Administration also recommends no more than 400 milligrams a day.

• Health Canada’s guidance on energy drinks

Just weeks after stopping his consumption of the energy drink, the man’s blood pressure returned to normal. Today, years after the incident, he is healthy but still lives with the aftermath of his stroke.

“I obviously wasn’t aware of the dangers drinking energy drinks were causing to myself,” the man told his doctors. “(I) have been left with numbness (in my) left hand side hand and fingers, foot and toes even after 8 years.”

Combinations of ingredients ‘cause havoc’

It’s not just high levels of caffeine. Today’s energy drinks also contain blood pressure boosting ingredients such as the amino acid taurine, Munshi said.

“Energy drinks that contain caffeine plus taurine produce significantly higher blood pressure than caffeine alone,” he said. “They also contain high levels of glucose — we know sugar damages the blood vessels in diabetes which leads to heart damage.”

Energy drinks also typically contain ginseng, which impacts metabolism, and guarana, a plant thought to contain caffeine at twice the concentration of a coffee bean, according to the study. Milder stimulants such as theophylline, found in cocoa, and theobromine, found in tea, are often included as well, Coyle said.

Such energy drinks can cause cardiac arrhythmias, damage the endothelium, the tissue that lines blood vessels, and aggregate blood platelets, Munshi said.

“When platelets are aggregated, especially in the setting of high glucose, they can produce blood clots,” he said. “Young people are often willing to try energy drinks, especially in combination with other drugs such as cocaine or methylamphetamine, which have similar effects, and all of these drugs together can cause havoc.”

Medical literature is full of examples of the harms of energy drinks, so this case, while startling, is not an isolated event, Munshi said.

“We have seen other patients who developed an irregular heartbeat, what we call atrial fibrillation,” he said.” Another patient developed an intracellular hemorrhage in the brain, while yet another patient had a stroke in the brain due to a blood clot.”

Munshi believes doctors need to become more aware of the impact of energy drinks and ask about use during regular checkups, “especially when people come at a younger age with cardiovascular problems or strokes.”

“The nature of these drinks is changing. They have become more and more dangerous and more potent,” he added. “We propose increased regulation of energy drink sales and advertising campaigns, which are often targeted at younger ages.”

By Sandee LaMotte, CNN