This could kill an energy drink lover’s buzz.
Consuming 32 ounces of energy drinks (two cans of Monster Energy Drink, made by Monster Beverage Corporation MNST, -0.82% or just under three cans of Red Bull) in under an hour spiked the risk of electrical disturbances in the heart for as long as four hours after the drinks were consumed, according to a small study published in Journal of the American Heart Association.
Thirty-four healthy volunteers between the ages of 18 and 40 were randomly assigned to drink 32 ounces of one of two commercially-available (but unidentified) caffeinated energy drinks, or a placebo drink, on three separate days. Both energy beverages had 304 to 320 milligrams of caffeine per 32 fluid ounces; in comparison, a Starbucks Pike Place roast packs about 330 milligrams for 16 ounces. The placebo contained carbonated water, lime juice and cherry flavoring. The beverages were swallowed within a 60-minute period, but no faster than one 16-ounce serving per 30 minutes, so the participants weren’t chugging two drinks back-to-back.
The researchers took electrocardiograms to measure electrical activity in the subjects’ hearts, for instance, the QT interval, or the length of time it takes the ventricles in the heart to prepare to beat again. They also recorded the subjects’ blood pressure. Both measurements were taken at the beginning of the experiment, and then every 30 minutes for four hours after the beverage was drunk.
The participants who gulped the energy drinks had a higher QT interval at four hours compared to the placebo drinkers, and their blood pressure increased, as well. QT intervals that are too short or too long can cause life-threatening heart arrhythmias, and increased blood pressure can lead to heart failure, stroke and aneurysms by damaging the arteries and the heart.
More research is needed, as this study was small, only featured healthy individuals, and didn’t take other factors into consideration (such as mixing the drinks with alcohol.) It also didn’t look at the long-term effects of energy drink consumption. But lead author Sachin A. Shah, professor of pharmacy practice at the University of the Pacific, wrote that the preliminary findings raise red flags.
“The public should be aware of the impact of energy drinks on their body, especially if they have other underlying health conditions,” Shah said in a statement. Healthcare professionals should advise certain patient populations, for example, people with underlying congenital or acquired long QT syndrome or high blood pressure, to limit or monitor their consumption.”
The American Beverage Association defended the safety of energy drinks like PepsiCo PEP, +0.42% Rockstar brand or Coca-Cola’s KO, -1.00% upcoming Coke Energy in a statement to MarketWatch, saying: “Energy drinks have been enjoyed by millions of people around the world for more than 30 years and are recognized by government food safety agencies worldwide… as safe for consumption… America’s leading energy drink manufacturers voluntarily go beyond all federal requirements when it comes to responsible labeling and marketing practices, including displaying total caffeine content from all sources and advisory statements that the drinks are not recommended for children, pregnant or nursing women, or those sensitive to caffeine.”
A 2017 Frontiers in Public Health review of energy drink research also associated energy drink consumption with risk-seeking behavior, mental health problems, increased blood pressure, dental problems, obesity and kidney damage. “The energy drink industry has grown dramatically in the past 20 years, culminating in a nearly $10 billion per year industry in the United States,” wrote Dr. Josiemer Mattei, Assistant Professor of Nutrition based at the Harvard T.H. Chan School of Public Health. “They are often marketed as a healthy beverage that people can adopt to improve their energy, stamina, athletic performance and concentration, but our review shows there are important health consequences, and little is known about many of their non-nutritive stimulants such as guarana and taurine.”
Indeed, it’s the combination of stimulants and sweeteners that appears to be problematic, rather than the caffeine or sugar alone.
Last fall, another American Heart Association study found that drinking just one energy drink narrowed blood vessels 90 minutes later, which increases the risk of blockages that cause heart attacks and strokes. The internal diameter of subjects’ blood vessels was much smaller after consuming the energy drink.
“As energy drinks are becoming more and more popular, it is important to study the effects of these drinks on those who frequently drink them and better determine what, if any, is a safe consumption pattern,” the paper read.
A 2018 study found 40% of teens aged 13 to 19 reported side effects from ingesting energy drinks, including heart palpitations, insomnia, feeling “jittery,” chest pain, labored breathing, and even seizures, nausea, vomiting and diarrhea. The U.S. military has also warned that energy drinks could do “serious harm” to troops’ bodies, and noted that soldiers in the field were more likely to fall asleep on duty if they consumed multiple beverages a day.
The global energy drink market was worth $39 billion in 2013, and is expected to hit $61 billion by 2021.