London  - Drivers who drink high energy drinks to keep themselves alert on long-distance trips are risking both their concentration and their health, warns the Institute of Advanced Motorists (IAM) in London.

Such caffeinated drinks can even lead to an increase in weariness behind the wheel, said the IAM. The institute quoted an alert issued by the US National Safety Commission linking the dangers of driving under caffeine intoxication with warnings normally associated with

drinking alcohol and driving.

High-energy drinks generally contain high levels of caffeine and sugar and in little more than an hour after consuming one tired drivers could expect to suffer serious lapses of concentration and lower reaction times.

Excessive caffeine consumption has a similar effect to alcohol intoxication, causing irritability, nervousness, irregular or rapid heartbeat, along with muscle twitching and speech problems, said the experts.

"Energy drinks are good as a quick fix, but they're no substitute for regular breaks. Having a high-caffeine drink is a one-off hit - you can't repeat it, as this type of drink does not produce the same effect in a couple of hours' time," said Neil Greig, IAM Director of Policy and Research.

To beat fatigue, the IAM suggests a number of measures: Motorists should share the driving with someone else, stop every two hours, stop when tired rather than relying on just opening a window or switching on the air-conditioning, and only get back behind the wheel when properly refreshed. (dpa)