U.S. poison control centers say they get a lot of calls about children and energy drinks. The reason, according to findings from a study done by the American Heart Association, is that kids can experience grave health risks when they chug caffeinated drinks, CNN.com reports.

The study showed that between 2010 and 2013, 40 percent of a little more than 5,000 energy-drink-related calls to poison centers involved children under age 6. These kids suffered from side effects that included abnormal heart rhythms and even seizures.

Additionally, researchers warned that small children can experience health problems after drinking just 100 milligrams of caffeine. That said, many energy drinks sold today contain more than 300 mg of the drug. What’s more, beverage companies aren’t required to report how much caffeine their products actually contain.

“We need to consider these energy drinks and their potential effects on the heart and vasculature and recognize that they are not benign,” said Laurence Sperling, MD, the medical director of preventive cardiology at Emory Healthcare in Atlanta.

To address the problem, researchers said they would like the government to require drink makers to reveal the caffeine content in their products. Also, scientists suggested adding an advisory label that warns these products aren’t recommended for children, or pregnant or nursing women.

High amounts of caffeine in the body can decrease the body’s ability to reabsorb potassium, an essential mineral that regulates the heartbeat. Click here for more information.