New research suggests adults who consume energy drinks pumped full of caffeine and taurine had a "significant" increase in heart contraction the following hour.
"Until now, we haven't known exactly what effect these energy drinks have on the function of the heart," radiology resident Jonas Dörner, M.D., of the cardiovascular imaging section at the University of Bonn, Germany, said in a Radiology Society of North America news release. "There are concerns about the products' potential adverse side effects on heart function, especially in adolescents and young adults, but there is little or no regulation of energy drink sales."
Teenagers and young adults used to be the target demographic for energy drinks, but recently people of all ages have started regularly consuming them, turning the market into a multi-billion-dollar industry.
Between the years of 2007 and 2011 the number of energy drink-related emergency room visits basically doubled. The number rose from 10,068 to 20,783, according to a report from the Substance Abuse and Mental Health Services Administration; most of the patients were between the ages of 18 and 25, followed by the 26 to 39 age group.
"Usually energy drinks contain taurine and caffeine as their main pharmacological ingredients," Dr. Dörner said. "The amount of caffeine is up to three times higher than in other caffeinated beverages like coffee or cola. There are many side effects known to be associated with a high intake of caffeine, including rapid heart rate, palpitations, rise in blood pressure and, in the most severe cases, seizures or sudden death."
The team used cardiac magnetic resonance imaging (MRI) to observe the effects of energy drinks on the heart. They looked at 18 healthy men and women with an average age of 27.5 years. They observed the participants' hearts one hour before and after consuming the drink.
The researchers found consuming the drink "significantly increased the peak strain and peak systolic strain rates (measurements for contractility) in the left ventricle of the heart," the news release reported.
The left ventricle has the crucial job of distributing oxygenated blood to the aorta; which in turn distributes it to the rest of the body.
"We don't know exactly how or if this greater contractility of the heart impacts daily activities or athletic performance," Dr. Dörner said. "We need additional studies to understand this mechanism and to determine how long the effect of the energy drink lasts."
The team did not find a significant difference between the patients' baseline and second MRI.
"We've shown that energy drink consumption has a short-term impact on cardiac contractility," Dr. Dörner said. "Further studies are needed to evaluate the impact of long-term energy drink consumption and the effect of such drinks on individuals with heart disease."
Doctor Dörner advised that children and people with a history of heart arrhythmias should abstain from the drinks.
