How Energy Drinks Affect Your Heart Rhythm

With energy drinks turning into a multibillion-dollar industry over the past couple decades, it is important understand what these drinks contain, how they affect our bodies and, for the purposes of this post, how they affect heart rhythm. We know, for example, that there have been reports of major cardiac events as a result of the misuse and even abuse of these drinks –where the sheer amount of caffeine and/or sugar consumed has sent some into cardiac arrest.

But how do we really know how much is too much?

Let’s explore a recent study published in the Journal of the American Heart Association1 that followed about three dozen healthy young adults who each consumed 32 ounces of two different energy drinks on separate days. Their blood pressure and heart rhythm were monitored at certain intervals over the next four hours. The bottom line was that a statistically significant increase in blood pressure and a significant increase in QT interval – which can cause the heart to begin beating irregularly – was clearly seen. There have been several other studies that look at the effects of energy drinks in smaller quantities such as 8 ounces, 16 ounces or even 24 ounces and have shown there to be less or no significant effect on the heart. 32 ounces seems to be the threshold at which point patients begin to feel the ill-effects.

While 32 ounces may seem like a whole lot, it’s not hard to fathom someone drinking four 8oz or just two 16oz cans of the stuff. First, they usually taste really good. Second, as the caffeine high starts to wear off, the natural reaction is to grab another can to keep it going. Over time, as the body develops a tolerance for the caffeine, one needs more to get the same energy-boosting effect.

Further, not all energy drinks are created same. Each beverage maker adds a different amount of sugar and caffeine into their drinks. A 32-ounce energy drink can conceivably deliver the equivalent of seven or even 10 cups of coffee – All in a very short time.

So What Are The Consequences?

Those with heart disease and existing blood pressure issues quite simply increase their risk of a major or catastrophic cardiovascular event by drinking energy drinks and pushing their blood pressure that much higher. Even healthy people may feel the long-term effects of a blood pressure increase day in and day out as the abuse starts to take its toll on the heart.

From an electrophysiologist’s standpoint, a longer QT interval represents a greater risk for irregular heartbeat or arrhythmia. While we did not have definitive data that energy drinks cause chronic long QT intervals, the potential consequences are significant enough to rethink consuming that much energy drink. Treatment for a long QT syndrome is mostly preventative and not curative. We often start with lifestyle changes – getting healthier – medications and sometimes ICDs or pacemakers to minimize fainting or serious cardiac events. Patients must also try to control their emotions that cause a rapid heartbeat. The patient’s lifestyle is often severely limited.

Ultimately, the energy drink business is poorly regulated, and the effects are not well understood, despite the surging consumption of these beverages. It stands to reason, however that moderating our intake of energy drinks is critical to keeping a healthy heart rhythm and avoiding some of the rare, but potentially very serious consequences of overconsumption.

1 Shah SA, Szeto AH, Farewell R, et al. Impact of High Volume Energy Drink Consumption on Electrocardiographic and Blood Pressure Parameters: A Randomized Trial. Journal of the American Heart Association. 2019;8(11). doi:10.1161/jaha.118.011318.

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