Commercial energy drinks have once again been linked to heart health concerns—this time by a study published today in the Journal of the American Heart Association.
And it’s not the fault of caffeine alone, the study results suggest.
Previous research has associated the mix of ingredients in some popular energy beverages with a host of heart issues. The energy drinks often contain high levels of caffeine as well as blends of vitamins, herbs, and other stimulants.
Reported heart problems have included elevated blood pressure, increases in the stress hormone norepinephrine, heart palpitations, and abnormal heart rhythms, in general, even in people with no cardiovascular risk factors.
The new research adds to the growing body of evidence that these drinks can be dangerous and send some to the emergency room.
“For the 1 in 3 Americans who already have hypertension, this increase in blood pressure from consuming energy drinks could pose a potentially serious risk,” says Emily A. Fletcher, Pharm.D., study author and deputy pharmacy flight commander at David Grant U.S.A.F. Medical Center at Travis Air Force Base in California, where the study was performed.
The study compared a caffeinated drink mixture to a commercial energy drink that also contains caffeine. The results suggest that caffeine alone in these drinks may not be responsible for the heart health problems.
Here’s what you need to know about energy drinks and your heart.
Beyond Caffeine: What the Study Found
Study subjects included 18 healthy men and women ages 18 to 40. Half were given a 32-ounce serving of an unspecified commercially available energy drink. The researchers would not reveal the name of the energy drink brand.
The others received a control drink: 32 ounces of carbonated water, cherry syrup, lime juice, and caffeine.
Both drinks contained 320 milligrams of caffeine, but the energy drink also contained what the manufacturer calls its “proprietary energy blend,” a mix that includes B vitamins, amino acids taurine and L-carnitine, the sugar alcohol inositol, and plant compounds such as panax ginseng extract and guarana extract.
Researchers measured the electrical activity of the subjects’ hearts and their systolic blood pressure (the top number) immediately before consumption of the drink, and 1, 2, 4, 6, and 24 hours after.
Two hours after drinking, the hearts of the study participants who’d consumed the energy drink showed temporary abnormal electrical activity—which could raise risks of a potentially life-threatening arrhythmia. The control group did not experience the effects.
Both groups showed an increase in systolic blood pressure for 4 hours after drinking. But those in the energy drink group still had significantly elevated blood pressure levels 6 hours after finishing their beverage, while the blood pressure of those in the control group had returned to normal.
Fletcher, the study author, suspects that the “proprietary blend” of ingredients in the…