London - Energy drinks high in caffeine change the way the heart beats and could increase the risk of potentially fatal heart rhythm problems, researchers have warned.
Healthy adults who consumed the drinks had significantly increased heart contraction rates one hour later.
This meant that the chamber of the heart that pumped blood around the body – the left ventricle – was contracting harder an hour after the energy drink.
The German researchers examined the effect of drinks high in caffeine and taurine – such as Red Bull-type drinks – on 18 healthy adults with an average age of 27.5 years.
Each of the volunteers underwent a MRI scan of the heart before and one hour after consuming an energy drink containing taurine (400mg/100ml) and caffeine (32mg/100ml).
After the drink, these people had “significantly increased peak strain” and contractility in the left ventricle of the heart – the part which receives oxygenated blood from the lungs and pumps it to the aorta, which distributes it throughout the rest of the body.
“Until now, we haven’t known exactly what effect these energy drinks have on the function of the heart,” said Dr Jonas Dörner, who works in the cardiovascular imaging section at the University of Bonn.
“Usually they contain taurine and caffeine as their main pharmacological ingredients and 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.
“We don’t know exactly how or if this greater contractility of the heart affects 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.”
The researchers found no significant differences in heart rate, blood pressure or the amount of blood ejected from the left ventricle of the heart before or after the energy drink was consumed.
However, Dörner said that while long-term risks to the heart from drinking energy drinks remained unknown, children, as well as people with known heart rhythm problems (cardiac arrhythmia), should avoid energy drinks because changes in contractility could trigger arrhythmias.
He said alcohol could increase heart rate, and mixing energy drinks with it could compound the problem.
“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.” – Daily Mail