The news is based on a small study of 18 healthy adults who had heart scans taken before and one hour after drinking an energy drink containing caffeine and taurine (a chemical said to have stimulant properties).
The study’s preliminary results were presented at the annual meeting of the Radiological Society of North America.
From an abstract of the presentation and a press release, it seems the researchers found that “strain rate”, a measure of the speed of heart muscle contraction, was significantly increased after the energy drink was consumed. However, the researchers found no changes to volume of blood pumped, pulse rate or blood pressure an hour after the energy drink.
The researchers gave the participants a drink containing 32mg per 100ml of caffeine and 400mg per 100ml of another chemical, taurine.
They demonstrated the chamber of the heart that pumps blood around the body, the left ventricle, was contracting more forcefully an hour after the energy drink was taken as compared to the beginning of the study.
Researcher Dr Jonas Dorner said: “Until now, we haven’t known exactly what effect these energy drinks have on the function of the heart.
“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.”
Dr Dorner added that it is not clear if the greater contractility of the heart affects daily activities or athletic performance. It has been proven only that consumption of these beverages has a short-term impact on cardiac contractility.
The effects on people with heart disease are not clear. However, the research team advises that children and people with an irregular heart beat should avoid the drinks. Given that many are unaware that they have certain heart conditions, it is possible that governments might move to ban them.