Energy drinks are the second most popular dietary supplement of choice for teenagers and young adults in the United States, according to the National Center for Complementary and Integrative Health (NCCIH).
A recent article in the American Journal of Preventive Medicine puts the rise in popularity of energy drinks into numbers.
The percentage of 12–19-year-olds consuming energy drinks in the U.S. has risen from 0.2% in 2003 to 1.4% in 2016. The highest increase was among young adults, aged 20–39, from 0.5% to 5.5% in this time period, while the figure rose from 0% to 1.2% in adults aged 40–59, according to the study’s authors.
Yet mounting evidence portrays energy drinks in a different light. “Consuming energy drinks raises important safety concerns,” according to the NCCIH, with twice as many emergency department visits related to energy drinks recorded in 2011 than in 2007.
In the largest randomized, controlled clinical trial on the subject to date, researchers from the University of the Pacific in Stockton, CA, along with collaborators from other institutions, identify how energy drink consumption affects the heart.
Heart rhythm altered
For the study, published in the Journal of the American Heart Association, lead study author Sachin A. Shah, a professor of pharmacy practice at the University of the Pacific, enrolled 34 adults aged 18 to 40.
After an overnight fast, the volunteers consumed two 16-ounce bottles of either one of two energy drinks or a placebo, which contained carbonated water, lime juice, and cherry flavoring. The study was double-blinded, meaning that neither the participants nor the researchers knew who drank which product.
The researchers then measured the volunteers’ heart rhythms with standard electrocardiogram and blood pressure readings every 30 minutes for a total of 4 hours.
Here they found a significant change in the time that the chambers of the heart needed to contract and relax. This measure is called the QT interval. The length of the QT interval is linked to a person’s heart rate, so scientists often use a corrected version, called QTc, that takes heart rate into account.