Can energy drinks kill you? Here are the dangers of caffeine overdose.

Anyone who's ever had one too many cups of coffee will recognize the point at which caffeine stops being productive and starts to make you feel slightly ill, with shaky hands and a fluttering heart. And that's definitely the case with energy drinks, too. But how dangerous is caffeine, and can energy drinks kill you? And if they're that dangerous, how many Red Bulls can you drink before you die? How many energy drinks is too many?

According to Healthline, caffeine overdose can lead to dizziness, diarrhea, insomnia, fever, vomiting, trouble breathing, uncontrollable muscle movements, convulsions, and an irregular heartbeat, among other scary symptoms.

And energy drinks, like Red Bull and Monster, include a number of energizing ingredients in addition to caffeine — and, according to Mayo Clinic Health Systems, they can also contain additional caffeine sources that are actually listed simply as an "energy blend" on the label. That may sound innocent enough, but the "blend" — which typically contains ingredients like taurine, glucuronolactone, guarana, and B vitamins — can also have pretty extreme side effects, including heart attacks, according to a study published in Mayo Clinic Proceedings.

But the human body can handle a fair amount of energy drink-induced unpleasantness before it ceases to function. How much — and how many energy drinks a person can consume before they die — depends on the individual. According to Mayo Clinic, most healthy adults can safely drink up to 400 milligrams (mg) of caffeine per day, which equates to about four cups of brewed coffee or two "energy shot" drinks. While all energy drinks vary, per the Center for Science in the Public Interest, a 16 oz can of Monster contains 160 mg of caffeine, and an 8.4oz can of Red Bull contains 80 mg of caffeine.

Caffeine Informer has a special calculator to help the energy drink imbibers determine how many of the stimulating beverages they can handle before their hearts give out.

Based on their math, a person who weighs 115 pounds, for example, could withstand:

- 48.2 8 ounce cups of brewed coffee

- 101.9 1.5 ounce shots of espresso 

- 98.1 cans of regular Red Bull 

- 49.1 cans of Monster Energy Drink

- 39.2 bottles of regular 5-Hour Energy

- 1,308.1 espresso beans 

- 313.9 8 ounce cups of green tea 

- 230.8 cans of regular Coca-Cola

And so on and so forth. Combine all of these and the result is almost certain death, but each number on its own represents this hypothetical person's threshold for the energy drink in question. It could be assumed that most people would experience some sweaty, wild-eyed puking before they actually expired — if that's the case, medical attention is never a bad idea.