Your Health Checkup: The Risk of Caffeinated Energy Drinks

A new study on the effect of energy drinks on heart rhythm and blood pressure sheds more light on the safety of these amped-up beverages.


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“Your Health Checkup” is our online column by Dr. Douglas Zipes, an internationally acclaimed cardiologist, professor, author, inventor, and authority on pacing and electrophysiology. Dr. Zipes is also a contributor to The Saturday Evening Post print magazine. Subscribe to receive thoughtful articles, new fiction, health and wellness advice, and gems from our archive. 

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I exercise every morning before I begin work. Some mornings I just feel beat, too tired to pump iron or bike, so in addition to my usual yogurt, banana, and cup of morning coffee, I’m tempted to chug down an energy drink to prime my motor. However, knowing how dietary supplements can be adulterated with unwanted and even dangerous contaminants, I’m leery of doing that. In addition, I’ve written that “Energy drinks are in a different class [of dietary supplements]. They often contain caffeine at significantly higher concentrations than coffee and tea, along with other energy-boosting substances, such as guarana, sugar, ginseng, yohimbine, and ephedra … Multiple reports relating the temporal association between ingesting energy drinks and heart rhythm problems, including sudden death, are of major concern.”

More and more people are consuming energy drinks; their market value is projected to increase to more than $60 billion by 2021. About a third of U.S. teenagers aged 12-17 consume energy drinks regularly. The number is even higher – 45 percent — for military personnel. Energy drinks sent more than 10,000 people to emergency departments in 2007. That number had doubled by 2011. The Food and Drug Administration has attributed over 30 deaths to energy drinks.

What is it about energy drinks that makes them dangerous? A new study helps answer that question.

Researchers at the University of the Pacific in California had 34 young (22 years old) healthy volunteers consume two 16-ounce bottles of one of two brands of caffeinated energy drinks or lime juice with cherry flavoring placebo on three successive days with a six-day washout period in between. The researchers measured blood pressure and recorded an electrocardiogram (ECG) every half hour for four hours after drink consumption.

They found that the caffeinated energy drinks increased systolic blood pressure (top number) by five mmHg and diastolic blood pressure by four mmHg compared with placebo. While the blood pressure change may seem small, a sustained increase in systolic blood pressure of only  two mmHg is associated with a seven percent increase in the risk of dying from a heart attack and a ten percent increased risk of dying from a stroke.

After each heartbeat, the heart requires a rest period to prepare for the next contraction. This time period measured on the ECG is called the QT interval and when prolonged, can increase the risk of sudden cardiac arrest. In the study, caffeinated energy drink A prolonged the QT interval by 6.1 msec compared with placebo and caffeinated energy drink B prolonged the QT interval by 7.7 msec compared with placebo. Once again, the changes may seem trivial, but in susceptible individuals, that increase in QT may be just enough to tip the person into having a life-threatening rapid heart rhythm leading to sudden cardiac arrest and death.

What’s the take-home message? My advice is to avoid consuming ALL caffeinated energy drinks. If you feel tired, your body is “talking to you” and you should listen to it. Rest, or if you must be active, pace yourself. Between consuming plastic and ultra-processed foods, skipping breakfast, and eating eggs, we have enough risks on our plates  —literally! Why add more by consuming caffeinated energy drinks? Avoid them.

Featured image: Shutterstock

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  1. Thanks for the reply, Dr Zipes. (I meant to say I’d love a reply right here, please. Thank you.) Sorry if I missed the 12/11/18 column. I tried to find it using the search bar and the closest I found to that date was 12/18/18. I’ll have to look harder when I have more time. The last 2 weeks of December were a total mess. I might even have comments on it. If I do, I’ve got egg on my face now.

    These topics ARE intertwined. If you’re so caffeined-out on the ‘energy’ drinks, you’re not going to be able to sleep anyway; causing a vicious cycle of no sleep even if you want to, and more dependence on this canned poison.

  2. Thanks for your comment. I have already written about getting the proper amount of sleep:

    Dec 11, 2018
    Your Weekly Checkup: The Dangers of Not Enough (or Too Much) Sleep

    Douglas P. Zipes, M.D.

  3. Dr. Zipes, I wish you would have mentioned how crucial it is to get a good night’s sleep BEFORE exercising before work! You say some mornings you feel beat or too tired to pump iron or bike. Okay, but is this because you DIDN’T get a good night’s sleep, or you DID but can sometimes feel that way anyway?

    I’m not trying to grill you or be disrespectful. This is an excellent article about these heart-attacks-in-a-can! Everyone needs to be aware of how horrible and dangerous they are, and the article is really thorough on it. Every time I go into the AM-PM Arco station mini-market to pay for gas, I see these guys buying anywhere from a few to several cans of Throttle, Monster, Rock Star or combinations thereof. Sorry to say it, but it’s usually men continuing to prove how dumb they are; how they don’t need ANY sleep EVER because they’ve got these drinks!

    I’m standing there wondering WHICH can of this stuff will be the killer? Which can is the Russian roulette bullet?

    What the article misses is WHY are these drinks so popular?? Besides Americans being a nation of caffeine, nicotine and a whole laundry list of other addictions, a big percentage of Americans HATE sleep! Hate the very idea of it as a “waste of time” or “completely unnecessary”!

    Sleep is as crucial as its ever been, even more than ever because of the totally messed up times we live in, largely caused by lack of sleep! How could anyone that isn’t a complete moron see sleep as unnecessary, or only for babies, young children, dogs and cats? Millions of ’em living in the U.S., that’s who!

    To sum it up in a nutshell, if you get the proper amount of sleep every night, you shouldn’t require anything more than a harmless glass of cool ice tea or healthy, flavored water if you need a mid-afternoon lift.

    Wouldn’t you agree? I’d love a reply right here, thank you.


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