Berlin - The mixing of energy drinks with alcohol, popular amongst partygoers wishing to increase their endurance on the dance floor, is potentially dangerous, the German authorities are to warn, according to a news report Friday.

The German institute for risk evaluation (BfR) believed the cocktail could disrupt cardiac rhythms, cause cramps and damage the kidneys, Der Spiegel magazine reported on its online edition.

The BfR, a statutory body established with government funding in 2002 to improve consumer protection in the area of health, has not yet made public its findings.

But according to Der Spiegel, the institute has documented cases of deaths resulting from the practice.

The BfR is reported to have informed the government of the risks, advising against mixing alcohol with energy drinks and against vigorous exercise after drinking them. (dpa)