Energy drinks loaded with caffeine and taurine increase heart contractions for a period of time, according to a new study. The effect could be dangerous; research is ongoing, The Huffington Post reported.
Though researchers don't yet understand the longer term consequences of increased contraction, it is generally assumed to be a negative effect, and is dangerous for those with a previous heart conditions such as cardiac arrhythmia, according to the press release.
"We don't know exactly how or if this greater contractility of the heart impacts daily activities or athletic performance," said Dr. Jonas Dörner, one of the researchers. "We need additional studies to understand this mechanism and to determine how long the effect of the energy drink lasts."
The study was important because -- unlike previous research -- it demonstrated a definitive change in heart function from energy drinks such as Monster or 5 Hour Energy, according to the release. If further investigation by University of Bonn, Germany researchers Dörner and Dr. Daniel K. Thomas can pinpoint the exact implications of excessive amounts of caffeine (three times that of coffee), it could lead to better regulation of the energy drink market, according to the press release.
"Until now, we haven't known exactly what effect these energy drinks have on the function of the heart," said Dörner. "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."
Dörner and Thomas took MRI images of participants' hearts before and after they consumed an energy drink. Images taken after consumption showed "significantly increased peak strain and peak systolic strain rates (measurements for contractility) in the left ventricle of the heart," according to the release. The left ventricle is responsible for pumping oxygenated blood into the aorta, where it is dispersed throughout the rest of the body.
The frequency of emergency room visits from energy drinks has doubled from 2007 (10,068) to 2011 (20,783), according to a report from the Substance Abuse and Mental Health Services Administration in 2013. Most of the cases involved individuals ages 18-25.
Dörner and Thomas did not find a link between caffeine and blood pressure, but previous research has found that high levels of caffeine increased systolic blood pressure, The Huffington Post reported.
