Energy Drinks May Be Risky for People with Genetic Heart Condition

A man pours an energy drink cocktail.
(Image credit: Ash Pollard/Shutterstock)

Consuming energy drinks may be particularly risky for people with a certain genetic heart condition, a new study from Australia suggests.

The study looked at 24 people who had inherited long QT syndrome, a condition that can cause dangerous irregular heartbeats. About one person in every 2,000 has this condition, the researchers said.

Participants in the study received either two sugar-free energy drinks containing a total of 160 milligrams of caffeine plus 2,000 mg of the chemical taurine, or a control drink, which consisted of juice that didn't contain any caffeine or taurine. A chemical that's often added to energy drinks, taurine has been purported to enhance mental and athletic performance. Participants in the study weren't told whether they'd received the energy drink or the control drink.

The results showed that participants' blood pressure increased significantly when they consumed the energy drink, compared to when they consumed the control drink, the study said.

What's more, after consuming the energy drink, three participants experienced a dangerous increase in a part of their heartbeat's electrical cycle known as the QT interval. This interval corresponds to the time it takes for the heart to contract and refill with blood, according to the Mayo Clinic. Although this prolonged QT interval doesn't always cause problems, it can trigger life-threatening irregular heartbeats in people with long QT syndrome. [10 Interesting Facts About Caffeine]

"The potential cardiovascular risk of energy drinks continues to emerge as an important public health issue," study co-author Dr. Christopher Semsarian, a cardiologist and professor at the University of Sydney in Australia, said in a statement. The researchers said that people with long QT syndrome should be cautious about consuming energy drinks.

Many previous studies have found links between energy-drink consumption and heart problems. For example, one study published in 2015 found that consuming just one energy drink can increase blood pressure in healthy people. And there have been several reports of young people who have suffered heart attacks or abnormal heart rhythms after consuming energy drinks.

Dr. Peter Schwartz and Dr. Federica Dagradi, of the Center for Cardiac Arrhythmias of Genetic Origin in Milan, Italy, who wrote an editorial accompanying the new study, said the findings deserve careful consideration. They noted that patients with long QT syndrome often don't discover they have the condition until after their teen years.

This "implies that a significant number of youngsters with [long QT syndrome] will help themselves to energy drinks without knowing their real condition and thus endangering themselves," Schwartz and Dagradi wrote.

Still, the researchers did not find an increase in the QT interval among all participants, which suggests that some people with the condition may be at higher risk than others for this effect.

The study and the editorial were published March 15 in the International Journal of Cardiology.

Original article on Live Science.

Rachael Rettner

Rachael is a Live Science contributor, and was a former channel editor and senior writer for Live Science between 2010 and 2022. She has a master's degree in journalism from New York University's Science, Health and Environmental Reporting Program. She also holds a B.S. in molecular biology and an M.S. in biology from the University of California, San Diego. Her work has appeared in Scienceline, The Washington Post and Scientific American.