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Hypertension/High Blood Pressure Health Center

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Energy Drinks Linked to Changes in Heart Rhythm

But more research is needed on the caffeine-laden beverages, review says


The QT interval is an electrocardiogram (EKG) measurement of how the heart resets itself electronically while it beats. A longer interval raises the risk that a "short circuit" will develop in the heart and possibly kill a person.

The review found that the QT intervals lengthened after people consumed energy drinks. Federal officials would raise an alarm if a medication produced this level of an effect, said review co-author Dr. Ian Riddock, a preventive cardiologist at the David Grant Medical Center at Travis Air Force Base, in California.

It's not known if the culprit is the caffeine or the other ingredients, "although we tend to think it's the latter," Riddock said.

One important question to answer, White said, is whether the effect on the heart goes up as people consume more of the drinks at a time or if it reaches a ceiling and stays there.

The review also found that the systolic blood pressure -- the top number in a blood pressure reading -- jumped by 3.5 points after participants consumed the drinks. That's not surprising considering the caffeine levels in the drinks, Riddock said. "But if this is going on [at] a chronic level, then it's worrisome," he said.

So what should consumers do? More research is needed, Riddock said, and "we need to start thinking about whether we need to regulate these things better."

The review findings were scheduled to be presented Thursday at an American Heart Association meeting in New Orleans. The report has not undergone the peer-review process that research must go through in order to be published in a scientific journal.

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