After drinking a 16-ounce can of "Rockstar Punched," young adults had a 74 percent increase in blood levels of the "fight-or-flight" hormone norepinephrine, said lead researcher Dr. Anna Svatikova, a cardiologist at the Mayo Clinic in Rochester, Minn. That's more than double an average 30 percent increase in norepinephrine the same participants experienced when they consumed a fake energy drink, Svatikova said. Blood pressure also spiked due to energy drinks. For example, mean blood pressure increased by 6.4 percent after energy drink consumption, compared with a 1 percent increase when the young adults downed the fake drink, the study found.The sham energy drink contained the same amount of sugar and nearly the same calories, but did not include natural stimulants found in the Rockstar drink, she said. The stimulants in the real energy drink include caffeine, taurine, guarana, ginseng and milk thistle extract.
These findings were presented at the American Heart Association's annual meeting in Orlando, and the results will be published simultaneously in the Journal of the American Medical Association. Energy drinks can contain up to five times more caffeine than a typical cup of coffee, according to the U.S. Substance Abuse and Mental Health Services Administration (SAMHSA). Emergency room visits involving energy drinks doubled between 2007 and 2011, rising from about 10,000 to nearly 21,000, SAMHSA said.
SOURCES: Anna Svatikova, M.D., cardiologist, Mayo Clinic, Rochester, Minn.; Linda Van Horn, Ph.D., R.D., professor, preventive medicine and nutrition, Northwestern University Feinberg School of Medicine, spokeswoman, American Heart Association; Nov. 8, 2015, presentation, American Heart Association annual meeting, Orlando, Fla.; Nov. 8, 2015.