The instant buzz you get after downing an energy drink gives your body a lift in other ways—increased blood pressure and a prolonged QT interval, which could spell heart problems.
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Results from a meta analysis of how energy drinks affect heart health weren’t all that surprising, but they do raise enough concern to warrant a deeper investigation. “Energy drinks typically accelerate heart rate because of their caffeine content or thyophyline effects. They have the same effect on the heart as adrenaline, and they may have additive effects when endogenous adrenaline is released,” says Patrick Tchou, MD, a cardiologist at Cleveland Clinic. “These effects can favor production of arrhythmias.”
If energy drinks were FDA regulated—and they are not—the beverages would be more thoroughly scrutinized. And, while moderate consumption of energy drinks probably wouldn’t cause a person to land in the heart clinic, a habit definitely isn’t a good idea. Study results uncover a definite change in a person’s vitals.
About the study
The study by Dr. Sachin Shah and colleagues at the University of the Pacific in Stockton, California, was presented at the Epidemiology and Prevention/Nutrition Physical Activity and Metabolism 2013 Scientific Sessions. In a literature search, they identified seven observational and interventional trials that evaluated the impact of energy drinks on QT interval, blood pressure and heart rate. QT interval is the portion of an electrocardiogram between the onset of the Q wave and the end of the T wave, representing the total time for ventricular depolarization and repolarization. A severely lengthened QT interval puts a person at risk of sudden death. But there are too many variables in this study to assess the true significance of the QT interval change, Dr. Tchou says.
“By itself, this small prolongation of QT interval in someone who does not have a genetic propensity for prolonged QT is unlikely to cause arrhythmias, but not everyone with a genetic propensity may know about this,” Dr. Tchou points out.
The study participants were all age 18 to 45, and underwent ECG and blood pressure testing before and just after drinking one to three cans of energy drinks. Red Bull, Full Throttle and Meltdown RTD were used. (Red Bull contains 80 mg of caffeine, compared with 35 mg in a 12-oz. Coke or 100 mg in an average cup of coffee.)
After drinking the energy beverages, subjects had a systolic blood pressure increase of an average 3.5 mm Hg. So, an occasional energy drink probably won’t harm a healthy individual, based on study results. But people who are older or with underlying cardiovascular disease could really suffer in the heart department if they regularly choose energy drinks.
Dr. Tchou’s advice
“There isn’t enough data now to make any definitive statements about energy drinks and risk of heart disease, but we know that consuming excess caffeine contributes to increased blood pressure, heart rate and QT intervals,” Dr. Tchou says. “In addition, in those patients that have a history of irregular heart rhythms, energy drinks may trigger their arrhythmia and should be avoided.”
Recent research: Carnitine and energy drinks
Recent studies conducted at the Cleveland Clinic have shown that carnitine, an ingredient found in energy drinks, may have detrimental cardiovascular effects. Therefore, Dr. Tchou adds, “I see no long term health benefits from drinking ‘energy drinks.’ These drinks may provide short-term competitive advantages in sports but at a likely cost to long-term health.”
A good rule to follow if you want a drink — reach for a glass of water instead and you’ll be 100-percent safe and replenish your body rather than potentially taxing the heart.