The consumption of energy drinks increases the blood pressure of healthy young adults, especially if they do not consume caffeine on a regular basis, a new study has found.

Energy drinks, which are popular among teenagers and young adults, can contain up to three times the amount of caffeine found in other caffeinated beverages such as coffee or cola.

US researchers gave 25 healthy young adults, aged between 19 and 40, a commercially available energy drink or a placebo drink. Changes in the participants' heart rates and blood pressure were assessed before consumption and 30 minutes later.

Comparisons between those who consumed less than 160mg of caffeine per day - the average amount found in one cup of coffee - and those who consumed more than 160mg per day, were also made.

The study found that those who consumed the energy drinks experienced a significant rise in their blood pressure. This effect was strongest in those who did not consume caffeine on a regular basis.

Overall, the blood pressure of people who did not consume caffeine regularly increased at least twice as much as those drinking the placebo.

"We know that energy drink consumption is widespread and rising among young people. Concerns about the health safety of energy drinks have been raised. We and others have previously shown that energy drinks increase blood pressure.

"Now we are seeing that for those not used to caffeine, the concern may be even greater. Consumers should use caution when using energy drinks because they may increase the risk of cardiovascular problems, even among young people," the researchers from the Mayo Clinic said.

They presented their findings at the American College of Cardiology's 64th Annual Scientific Session in San Diego.