There’s a life or death warning you should know about: sipping energy drinks can be potentially fatal! And teens are most at risk!

It may sound like an exaggeration – but over the last few years, the number of people rushed to the ER because of energy drink-triggered issues has spiked 1,000%. And the FDA is now investigating whether or not to slap warning labels on energy drinks - after a string of recent deaths and heart attacks, allegedly linked to energy drink consumption.

So, what makes energy drinks dangerous? The caffeine content. Because some super-size energy drinks have seven times the caffeine of a can of Coke. And when all that caffeine enters your system, it can speed up your heart rate and increase blood pressure. Plus, our bodies absorb caffeine quickly. It shows up in the blood five minutes after drinking it. And if you’re taking certain medications – like antibiotics or asthma medication – it can linger in the system longer, building up.

And while that’s dangerous for anyone, teens are most at risk because they often guzzle energy drinks all day long. Another scary factor? A lot of teens have undiagnosed heart conditions that can make it harder – or impossible – for their heart to deal with all that caffeine. That’s what happened to one 14-year-old girl recently. She died after drinking two 24-ounce Monster Energy Drinks – which had the caffeine equivalent of 14 cans of Coke, or 5 tall Starbucks’ coffees. Doctors ruled her cause of death as cardiac arrhythmias caused by caffeine toxicity.

So, how much caffeine is too much? There’s no magic number – since everyone’s body reacts differently. Some people don’t even get the jitters. But experts say that energy drinks should be off limits for teens and those with heart conditions.