Energy drinks can trigger serious heart reactions in people who unknowingly have genetic heart conditions.
A heart condition which affects one in every 2000 people can be triggered by the drinks causing their hearts to beat rapidly and irregularly.
The reaction can even lead to sudden death, according to Australian scientists.
These are people who have a condition known as congenital long QT syndrome (LQTS) and many of them are unaware of their condition.
The study at the University of Sydney and Centenary Institute in Australia found that teenagers and young adults were most at risk since they were the target market for these drinks.
The researchers said even small amounts of energy drinks could “cause changes in the heart that can lead to life-threatening arrhythmias” in those with LQTS.
Previous studies have shown the drinks can increase blood pressure but not the heart rate.
“A significant number of youngsters with LQTS will help themselves to energy drinks without knowing their real condition and thus endangering themselves,”
explained Prof Peter Schwartz, head of the centre for cardiac arrhythmias of genetic origin in Milan in Italy.
The study showed that 12.5pc of patients with the condition showed a dangerours heart reaction and two thirds of these had sharp increases in blood pressure.
The researchers said they did not was to spread unjustified alarms and fears “but at the same time, we should not ignore potential dangers”.
They recommended caution in allowing young patients with LQTS to consume these energy drinks.