Red Bull and Rockstar brand energy drinks are put to the test.

The first energy drink (ED), Dr. Enuf, was launched in 1949, more than 70 years ago. Today, there are more than a hundred different brands in an industry now selling $50 billion a year in beverages.

Energy drinks are popular on military bases, but some “military leaders have questioned the safety of EDs,” based on the skyrocketing number of energy drink-related emergency room visits over recent years. You can see below a graph depicting this and at 0:26 in my video Are There Risks to Energy Drinks?. However, if you look at some of the reports, you see cases like this: A 24-year-old man didn’t feel well after drinking a can of energy drink and three bottles of vodka.

“Consumption of ED masks the signs of alcohol inebriation, enabling an individual to believe they can still safely consumer more alcohol, leading to ‘awake drunkenness.’” And, since because energy drinks are often co-consumed with other substances, it’s hard to tease out the culprit. It’s the same problem with population studies. Sure, “adolescents drinking energy drinks are at risk of a wide range of negative outcomes,” but energy drink consumers are also more likely to drink soda and have other unhealthy habits, and be more likely to binge drink, take diet pills, and engage in other risky behaviors, as you can see below and at 1:07 in my video. So, the only way to tease out the energy drink component is to put it to the test.

One of the concerns that has been raised by public health advocates in terms of potential negative effects is increased blood pressure. A half hour after study participants chugged an 8-ounce can of Red Bull, researchers found no significant change in blood pressure, though. What about a big 16-ounce can of Red Bull? Forty minutes after consumption of the larger can with double the volume, still no significant change was found, so concerns about energy drinks raising blood pressure were dismissed as overblown. That is, until the bomb dropped in 2014.

Red Bull does significantly raise blood pressure after all. The reason it was missed by the earlier studies is because the spike doesn’t begin peaking until about an hour after consumption, as you can see in the graph below and at 1:59 in my video. So, if you look at blood pressure levels 30 and even 40 minutes after consumption, everything seems fine, but the worst is yet to come. And, the big shocker was that cerebral blood flow velocity—that is, velocity of blood flow in the brain—took a dive. Energy drinks are promoted as having “beneficial effects on body and mental strength,” but this instead would suggest they’re “potentially harmful because of the extra cardiac work load and the decreased cerebral [brain] blood flow velocity observed during resting conditions.”

Researchers subsequently looked at other energy drink brands. In one study, a Rockstar energy drink significantly elevated blood pressure within just 30 minutes—but was it just the caffeine? Is having a Rockstar drink any different from just having a cup of coffee? To figure that out, you’d have to compare the effects of an energy drink with a plain drink with the exact same amount of caffeine, which is precisely what researchers did.

A randomized, double-blind, controlled, crossover study randomized young healthy volunteers to drink two large cans of an energy drink or a control drink that had the same amount of sugar and the same amount of caffeine, but none of the energy drink’s other “proprietary blend ingredients,” like taurine, carnitine, ginseng, and guarana.

It turns out it wasn’t just the caffeine. Those who drank the energy drink had “significantly higher” blood pressure than those in the control group, even though they drank the exact same amount of caffeine. The researchers also found that those drinking the energy drink had a higher “QT interval.” “QT”? Let me explain, and you can see for yourself below and at 3:30 in my video. On an EKG, a QT interval is the distance from the beginning of the downward Q wave to the end of the bump of the T wave. This is relevant because QT prolongation, which is what was caused by the energy drink but not the caffeinated beverage consumed by the control group, is “a recognized marker of increased risk for fatal arrhythmias”—that is, fatal heart rhythms. That doesn’t sound good, but by how much? “Prolongation of the QT…interval by more than 60 ms [milliseconds]…is a marker for life-threatening arrhythmias.” The energy drink only prolonged it by about 10 milliseconds, though. Well, drugs—profitable drugs bringing in billions of dollars—have been pulled from the market because they caused a 5- to 10-millisecond prolongation. So, we really need to start investigating some of these other ingredients in energy drinks.

In 2008, for example, authorities found cocaine in Red Bull drinks, but the “Red Bull manufacturers insisted that active cocaine was removed from the coca leaf during processing and that the extract was used for flavoring.”

For more on energy drinks, see my video Are There Benefits of Energy Drinks?.

What about coconut water? Check out Coconut Water for Athletic Performance vs. Sports Drinks.