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Is Caffeine Poisoning Real? An Expert Weighs In.

March 3, 2023

The term “caffeine poisoning” has gained some popularity over the past few days due to a report of a college athlete who allegedly experienced it. Matthew Mayer, a basketball player for the University of Illinois, recently reported that he was out sick due to alleged caffeine poisoning. Mayer said that he consumed an energy drink before a game against Ohio State on Sunday, Feb. 26, then consumed five more energy drinks after the game as he played video games.

According to CBS Sports, Mayer was sick in bed the following week due to “caffeine poisoning,” which he states is “basically like a caffeine hangover.”

But is that really true? Can you experience caffeine poisoning as the college athlete claims? We asked our expert Kelsey Kunik, RDN, if caffeine poisoning is actually real, and how a person can come to experience it.

Caffeine poisoning is possible—but you have to consume a lot of it.

While it may not be particularly known as “caffeine poisoning,” Kunik does confirm that you can experience an overdose of caffeine.

“Caffeine is a stimulant drug, and while over 85% of adults have some amount of caffeine each day, it is possible to overdose,” says Kunik. “Drinking too much caffeine could lead to irregular heartbeat, seizures, confusion, elevated blood sugar, or low potassium.

Also known as caffeine toxicity, when you reach toxic levels of caffeine in the liver (similar to alcohol), the body could experience a number of health complications.

“In extreme cases, caffeine overdoses can cause kidney injuries and even cardiac arrest,” Kunik continues. “In the rare cases of caffeine poisoning that have led to death, up to 10 grams or 10,000 milligrams of caffeine was ingested. For reference, one cup of coffee has about 100 to 150 milligrams of caffeine.”

How much caffeine is considered too much in a day?

Healthy adults can safely consume up to 400 milligrams of caffeine in a day, according to the Mayo Clinic. Because an average cup of coffee (8 ounces) includes around 100 grams, that means you can safely consume four cups of coffee in a day—or 28 ounces.

Mayer’s six energy drinks during the day had him averaging over 800 milligrams of caffeine in a day, far exceeding the safe limit. Given that a typical energy drink has around 140 milligrams per can, sipping on one is still safe for consumption, while consuming five or six at once would be unadvisable and dangerous.

Energy drinks can still be safe to consume, and even beneficial for athletes.

“Energy drinks are completely acceptable for athletes when taken responsibly,” Kunik says. “Research has found that caffeine can improve exercise performance in doses of 3 to 6 milligrams per kilogram of body weight. That’s 272 milligrams to 546 milligrams on the high end for someone who’s 200 pounds.”

The research Kunik refers to is a 2021 review published by the Journal of the International Society of Sports Nutrition, which confirms that caffeine in small to moderate doses can enhance “muscular endurance, movement velocity and muscular strength, sprinting, jumping, and throwing performance” and energy drinks, in particular, “have been demonstrated to enhance both anaerobic and aerobic performance.”

It’s not surprising that consuming six energy drinks in a day can easily lead to caffeine overdose, or as the athlete called it, caffeine poisoning. However, given the ways that energy drinks can benefit athletic performance, it isn’t correct to say that these drinks are to blame. Like consuming any food or beverage, it’s all about moderation.

This is why it’s important to keep an eye on your caffeine intake throughout the day, and if you choose to drink an energy drink for sports performance or simply as your daily pick-me-up, be sure to check your labels and keep your total caffeine intake throughout the day in mind.

Read next: This Popular Sweetener Has Been Linked to Heart Attacks, Says New Study

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