Energy drinks have become a multi-billion dollar industry that continues to grow, yet regulation of this enterprise remains largely unchecked. Now, a new study shows that healthy adults who consume energy drinks have "significantly increased" heart contraction rates an hour later.
The research was recently presented at the annual meeting of the Radiological Society of North America (RSNA).
The study authors, including Dr. Jonas Dörner from the University of Bonn, Germany, note that although the largest consumers of energy drinks have traditionally been teens and young adults, people from all demographics have begun to consume such drinks in recent years.
"Until now, we haven't known exactly what effect these energy drinks have on the function of the heart," says Dr. Dörner.
Meanwhile, a 2013 report from the Substance Abuse and Mental Health Services Administration revealed that from 2007 to 2011 in the US, energy drink-related emergency department visits doubled, climbing from 10,068 to 20,783.
The researchers note that most of these cases occurred in patients between the ages of 18 and 25, but this was followed by patients aged 26 to 39.
Dr. Dörner talks about the contents of these drinks:
"Usually energy drinks contain taurine and caffeine as their main pharmacological ingredients. The amount of caffeine is up to three times higher than in other caffeinated beverages like coffee or cola."
He adds that side effects associated with consuming a large amount of caffeine include a rapid heart rate, palpitations, rise in blood pressure and even seizures or death.
Energy drinks prompted increased strain in left ventricle
For their recent study, which is currently ongoing, the researchers measured the effect of energy drinks on heart function using cardiac magnetic resonance imaging (MRI).
Study participants consist of 15 healthy men and three healthy women, with an average age of 27.5 years.
The team took cardiac MRIs of the participants both before and 1 hour after they consumed an energy drink, which contained 400 mg/100 ml taurine and 32 mg/100 ml caffeine.
Results show that compared with the images taken before the participants consumed the energy drinks, the post-beverage MRIs showed that they had increased peak strain and peak systolic strain rates in the heart's left ventricle.
The researchers note that the left ventricle receives oxygenated blood from the lungs, which it then pumps to the aorta for distribution to the rest of the body.
Though the team observed this significant change, they say they do not yet know whether it impacts daily activities or athletic performance.
"We need additional studies to understand this mechanism and to determine how long the effect of the energy drink lasts," says Dr. Dörner.
Contractility changes could trigger arrhythmias
The team notes that they did not find any major differences in heart rate, blood pressure or the amount of blood pumped from the left ventricle after the participants consumed the energy drink.
However, Dr. Dörner says their results show that consuming energy drinks does have a "short-term impact on cardiac contractility."
The researchers say further studies are needed to assess the long-term effects of energy drink consumption, as well as any effects these drinks have on people with heart disease.
Despite the lack of knowledge about long-term risks, the team recommends that children and people with cardiac arrhythmias refrain from consuming energy drinks, as contractility changes could trigger arrhythmias.
A popular drink on the nightclub scene mixes energy drinks with alcohol, and Dr. Dörner warns that additional studies are needed to analyze the risks posed by such combinations.
Medical News Today recently reported that a compound in energy drinks raises heart risks via gut bacteria.