London, Sep 1 (IANS): "Energy" drinks which are so popular during physical exercise and even otherwise among children and younger adults can cause heart problems, a research shows.

"People sometimes consume a number of these drinks one after the other. This situation can lead to a number of adverse conditions, including angina, cardiac arrhythmia (irregular heartbeat) and even sudden death," warned professor Milou-Daniel Drici from France.

Speaking at the European Society of Cardiology (ESC) Congress, 2014, in Barcelona, Spain, he said that around 96 percent of these drinks contain caffeine, with a typical 0.25 litre holding as much as two espressos worth of caffeine.

"We found that caffeine syndrome was the most common problem. It is characterised by a fast heart rate (called tachycardia), tremor, anxiety and headache," he informed.

Caffeine is one of the most potent agonists - a chemical that binds to a receptor and activates the receptor to produce a biological response - of the ryanodine receptors and leads to a massive release of calcium within cardiac cells.

This can cause arrhythmias but also has effects on the heart's abilities to contract and to use oxygen.

The current study analysed adverse events reported to A.N.S.E.S - the French agency for food safety.

The researchers found that consumption of the 103 energy drinks in France increased by 30 percent between 2009 and 2011 up to over 30 million litres.

"Doctors should warn patients with cardiac conditions about the potential dangers of these drinks and ask young people in particular whether they consume such drinks on a regular basis or
binge drink," Dr Drici concluded.