A study from the University of Texas finds the consumption of energy drinks to have negative effects on the cardiovascular system by narrowing blood vessels that carry oxygenated blood as soon as 90 minutes.
Vessels that supply the heart, which may already be narrowed due to atherosclerosis, could narrow even more.
Moreover the restriction of blood flow to vital organs implies the brain may not receive the optimal circulation it needs.
How dangerous are energy drinks?
The study was conducted by scientists who looked at the endothelial lining of blood vessels in 44 healthy non-smoking students and found within 90 minutes of drinking a 24 oz energy drink the vessel dilation dropped from 5.1% in diameter to 2.8% in diameter.
Now energy drinks contain various levels of caffeine, as explained below. But they also contain taurine, sugar, vitamins and other ingredients. This study did not look specifically at caffeine but energy drinks, so the authors can’t specify what’s the culprit.
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Last year, however, a South Carolina high school student collapsed in class and later died from allegedly consuming an energy drink. The coroner’s report, revealed cited caffeine as the cause. The caffeine induced a cardiac arrhythmia, abnormal heart rhythm, and 16-year old Davis Allen Cripe tragically died within an hour.
What’s shocking is the amount of caffeine he ingested was not very high. According to Richland County Coroner Gary Watts, Cripe drank, within a two-hour period, a large Mountain Dew, an energy drink, and a cafe latte from McDonalds. The teen had no medical problems or family history of heart issues.
A large Mountain Dew contains 54 mg per 12 fluid oz. So a 20 oz drink would be close to 100 mg caffeine.
Energy drinks, depending on the brand, contain approximately 80 mg of caffeine per can.
A cafe latte from McDonalds, medium size, contains 142 mg of caffeine.
This in total would equal approximately 320 mg of caffeine ingested within a two-hour period.
The lethal dose of caffeine in adults range from 150-200 mg/ kg body weight. So a 70 kg adult could consume a toxic level of caffeine at 10 grams (10,000 mg).
So 320 mg of caffeine is well below the toxic level. But what caffeine could do could be the more dangerous part.
Caffeine has been known to induce arrhythmias. It’s a stimulant, hence it can affect the heart’s electrical conductivity that manages the organ’s pumping action. Once the electricity is disrupted, the heart muscle fails to have a predictable, rhythmic stimulation, hence cannot pump effectively.
Caffeine also causes vasoconstriction, so blood flow to the heart could be compromised, potentially inducing a heart attack.
In 2014, researchers from Barcelona found energy drinks to be linked to rare cases of heart attack and arrhythmia.
A cup of coffee averages 95mg of caffeine whereas an energy drink contains 80mg. But the latter is consumed much quicker than a hot cup of Joe that needs to be sipped, hence the consumer takes in a larger load of caffeine in a shorter amount of time. This could be too much too fast for the heart.
The following is a chart of average caffeine content in common drinks:
Image from Business Insider
I can’t convince everyone to reach for a piece of broccoli rather than an energy drink when in need of a boost, but at the very least we should deter use by children and teens, and educate those with vulnerable hearts, blood pressure, diabetes, kidney and liver issues that an energy drink may not be the wisest beverage choice.
Daliah Wachs, MD, FAAFP is a nationally syndicated radio personality on GCN Network, KDWN, and iHeart Radio.
She is also a Board Certified Family Physician and Assistant Professor at Touro University Nevada