In moderation, caffeine can have beneficial effects. But in larger doses it can put your health, and in rare cases, even your life at risk. Share on Pinterest Last month Davis Allen Cripe, a healthy teenager from South Carolina, died after downing a McDonald’s latte, a large Mountain Dew soda, and a highly caffeinated energy drink. According to a South Carolina coroner, the mixture of beverages led to a “caffeine-induced cardiac event causing a probable arrhythmia.” The coroner was careful to say that “this was not a caffeine overdose.” But the incident has still raised questions about the safety of caffeine, especially when ingested in large amounts over a short period of time. Read more: Effects of caffeine on the body »

Caffeine overdose is rare Caffeine overdose is quite rare. It usually involves high doses of caffeine taken in powder or tablet form, not beverages. The reason is simple. “It’s very hard to get that much caffeine when you’re drinking beverages because of the time it takes to drink them,” Jennifer Temple, PhD, associate professor of exercise and nutrition sciences in the University at Buffalo School of Public Health and Health Professions, told Healthline. The lethal dose of caffeine for most people, says Temple, is about 10 grams, although this varies from person to person. A cup of coffee has around 100 to 200 milligrams of caffeine. An energy drink contains anywhere from 50 to 300 mg of caffeine. A can of soda typically has less than 70 mg. So even with the most highly caffeinated energy drink, you would still have to drink around 30 of them in rapid succession to reach the 10 g range. Chances are, if you tried to drink that much, your body would stop you before you reached toxic levels. “Most of the time, if people have acute symptoms of caffeine toxicity, it starts with nausea and vomiting,” said Temple. “So usually that’s sort of protective because you just get sick and you throw up the caffeine before it becomes too toxic.” With caffeine powder or tablets, though, you can ingest a large amount at the same time. A teaspoon of the powder has 3,200 mg of caffeine. Read more: Facts about caffeine overdose »

Benefits and risks of caffeine Around 90 percent of adults in the world consume caffeine daily — in the form of coffee, tea, soda, energy drinks, and other beverages. Even chocolate contains small amounts of caffeine. Caffeine has many effects on the body, not all of them harmful. “The research that we’ve done in our lab, and the research that has been done in many other labs around the world, shows that in moderate doses, caffeine is probably not harmful,” said Temple. Some studies show that caffeine can increase alertness, mental energy, and concentration, especially in people who are tired. And, of course, there’s the big one. “The primary effect of caffeine, and the reason why people consume it, is that it counteracts fatigue,” said Temple. Of course, the downside of using caffeine to stay awake is not being able to sleep. At moderate doses — a couple of cans of soda or cups of coffee — caffeine increases a person’s blood pressure and decreases the heart rate. Some people, though, can drink several cups of coffee a day and hardly feel the effects. Others have trouble sleeping after eating too much chocolate before bedtime. Genetics may play a role in determining why some people are more sensitive to caffeine. Underlying health problems — like those that involve the heart — or medications can also lead to a stronger reaction to caffeine. And people who consume caffeine less frequently may be able to tolerate it less. Temple’s research also found that caffeine can affect boys and girls differently after puberty. Read more: Is there such a thing as safe energy drinks? »