Energy drinks - with high sugar and caffeine content - can lead to heart problems, a new study states.

Several researches have linked energy drinks to adverse health effects. What's problematic is that these drinks are considered safe, especially by teenagers. The high caffeine level in these drinks can alter heartbeats and raise risk of health complications.

"So-called 'energy drinks' are popular in dance clubs and during physical exercise, with people sometimes consuming a number of 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," said Milou-Daniel Drici from France.

For the study, the researchers used data from A.N.S.E.S - the French agency for food safety. Cardiologists, psychiatrists, neurologists and physiologists contributed to the investigation and it involved information on energy drink consumption in France between  2009 and 2011.

The researchers said that as much as 30 million litres of 103 energy drinks was consumed in France during the study period. Around 257 cases of energy-drinks related problems were reported to A.N.S.E.S in the two years of the study.

The team found that 95 of the cases had cardiovascular symptoms, while 57 had neurological. At least 8 people died due to unexplained causes, while 46 had heart rhythm disorders.

"We found that 'caffeine syndrome' was the most common problem, occurring in 60 people. It is characterised by a fast heart rate (called tachycardia), tremor, anxiety and headache," Drici said in news release.

A recent report from a U.S federal agency had said that ER visits linked to drinking too much energy drinks doubled from 10,000 in 2007 to almost 21,000 in 2011.

The study findings were presented at ESC Congress 2014.