Energy drinks can contain double or triple the caffeine of one cup of coffee, and the combined effects of ingredients such as taurine, ginseng, guarana and other stimulants can be difficult to measure. With new and extreme varieties of energy drinks flooding the market, health experts question whether current FDA regulations are enough, especially since the target demographic is primarily high school and college students.
A 2013 report from the Substance Abuse and Mental Health Services Administration found that energy drink-related ER visits doubled between 2007 and 2011. Robert Genzel, M.D., an emergency physician on staff at Texas Health Harris Methodist Hospital Fort Worth, has treated ER patients with side effects from energy drinks.
"They come in with anxiety attacks or a racing heart," Genzel explains. "Usually it is dose-related. It's not that they did one energy drink-it's several energy drinks, or they aren't accustomed to caffeine.
Those who consume too many stimulants over a short period may suffer adverse effects, including anxiety, nervousness, jitteriness, dizziness, headaches, insomnia, dehydration, nausea and heart palpitations. Less common but documented effects include allergic reactions, seizures, cardiac arrest and death.
Research from the American Heart Association found that between one to three energy drinks is enough to raise blood pressure and negatively affect heart rhythm, even triggering a cardiac event or death in certain people, particularly those with a pre-existing heart condition or family history of heart arrhythmia.
"Certainly if you're getting chest pain, shortness of breath or feeling light-headed, then you do need to come in [to the ER] and be evaluated," says Genzel.
How much is too much? Genzel suggests limiting consumption to one per day, less if you are caffeine sensitive, and avoiding energy drinks if you have a heart condition. Also, pay close attention to serving size.
"A lot of times you see the amount of caffeine in an 8-ounce drink, but they're selling them as 16, 24 or 32 ounces…so the caffeine load is immense," warns Genzel.
