His heart stopped and he needed defibrillation from ambulance officers. Now facing six weeks off work, he said warning labels on the products should be revamped to alert people that excessive consumption could lead to death. Labels currently warn against consuming more than two cans, or 1.5 bottles a day, without describing the consequences.

"They say [on energy drink labels] don't have more than this much," Mr Penbross said. "But they don't say if you have too much, what will happen." Dr Malcolm Barlow, a cardiologist who treated Mr Penbross at Newcastle's John Hunter Hospital, said it appeared excessive consumption of energy drinks had precipitated the heart attack.

He said Mr Penbross had no other risk factors apart from smoking and had told him he previously experienced chest pain at times when his intake of the drinks was high. NSW Health has urged people to be extremely cautious of overdosing on stimulant products. Department spokesman Dr Robert Batey said consuming high levels of stimulants had the potential to cause heart attacks.

"It will raise blood pressure and pulse rate and both of those things put a significant demand on the heart." Mr Penbross, a concreter, regularly had four Red Bull drinks a day. "With the work I do I don't have a lot of time to eat," he said. "I have a couple of Red Bulls in the morning and it carries me through."

Last Sunday he was competing in a motocross event near Port Macquarie when he consumed eight Red Bulls over five hours. "It was to get a bit of a buzz and keep down my reaction time," he said. "You have got to get off [the mark] and around the first corner first."

After his event, Mr Penbross, from Bonny Hills, noticed his heart racing. He collapsed soon after He was taken to Port Macquarie Hospital before being flown to Newcastle. There is no history of heart disease in the family and Mr Penbross is in peak physical condition.

Mr Penbross said he had sworn off Red Bull. A spokeswoman for Red Bull said she was unable to comment on Mr Penbross's case, but that the product label was clear in advising against excessive consumption. She said labelling requirements for energy drinks were set by the Federal Government.

IN THE CAN Red Bull contains: carbonated water, sucrose, glucose, acid (sodium citrates), taurine (0.4pc), glucuronolactone, caffeine (0.03pc), inositol, vitamins (niacinamide), pantothenic acid (B6, B12), flavours, colours (caramel, riboflavin). Each can contains 80 milligrams of caffeine.