Bad news for Red Bull addicts. 

By Elisabeth Sherman
Updated June 05, 2017
Bloomberg / Contributor / Getty Images

Science has finally proven what might seem obvious point most people: Energy drinks are worse for your health than soda.

A new study from the Journal of the American Heart Association studied 18 women and men, divided into two groups. Half were given a 32-ounce energy drink, which contains 320 mg of caffeine. For reference, one 8-ounce cup of coffee contains 95 mg of caffeine, while one 12-ounce can of soda contains 29 mg of caffeine. The energy drinks also contained the dietary supplements taurine (which supposedly boosts athletic performance) and gingseng. The other group was given a caffeinated control beverage flavored with lime juice, cherry syrup, and carbonated water to resemble soda. After six days, the groups switched drinks.

Researchers measured the heart activity and blood pressure of the study’s participants before and after drinking the beverages. They paid special attention to their QT interval—the time it takes for the heart to contract and relax in order to pump blood through out your body. The people who drank the energy drink had a QT interval that was 10-milliseconds higher than those who drank the control beverage, which doesn't sound like much, but is important because irregularities in these intervals can lead to an abnormal heart beat.

Both groups had higher blood pressure after drinking the caffeinated beverages, with one striking difference: The blood pressure of the people who drank the control beverage returned to its normal rate after six hours. The blood pressure of the people who drank the energy drink remained elevated for more than six hours. The study’s authors think that means that the additional ingredients—as well as high level of caffeine—are effecting consumers blood pressure.

Although the American Beverage Association insists that energy drinks are safe to drink—despite the fact that one 2008 study found that sugar free Red Bull doesn’t give you wings, it gives you blood clots—the study’s lead researcher, Emily Fletcher, still recommends enjoying energy drinks only in moderation, especially if you have a history of heart problems.

Fletcher adds one further blow to the energy drink industry: She also recommends avoiding energy drinks during activities that will heighten your blood pressure like “exercise or sports,” eliminating one of their major purposes for existing in the first place.