The high levels of caffeine in energy drinks may lead to cardiac complications, suggests a case report in the July-August issue of Journal of Addiction Medicine, the official journal of the American Society of Addiction Medicine. The case adds to previous reports of adverse cardiovascular events related to consuming energy drinks, including abnormal heart rhythms.
Researchers at the University of Florida, Gainesville (US), recently examined a 28-year-old man seen in the emergency room after vomiting blood. On examination, the only abnormality was a very fast heart rate: about 130 beats per minute. An electro-cardiogram revealed an abnormal heart rhythm called atrial fibrillation that can lead to serious complications if sustained. Further tests showed no other heart problems.
The patient routinely drank energy drinks for a total caffeine content of 320 mg. The researchers pointed out the 160 mg caffeine content in an energy drink is about four times higher than in a caffeinated soft drink. No other common causes of his heart rhythm abnormality were apparent in the patient.
A review of medical research has identified at least eight cases of cardiovascular events linked to energy drinks, which have become increasingly popular in recent years, especially among adolescents and young adults. Sold as “nutritional supplements,” these beverages are not subject to the caffeine limits on soft drinks, or to the safety testing and labelling required for medications.