Caffeine levels have increased in energy drinks since they became readily available in the 1980's and now there have been major concerns over the safety of these quick-fix liquid supplements.

It is widely documented that caffeine can boost your mental and physical performance – although there is no extensive benefit when your intake is less than 3mg per kg of body mass. Red Bull contains as much caffeine as a cup of coffee (around 80mg), while the controversial US energy drink, Cocaine, boasts a massive 280mg, more than three times as much.

In 2007, Dr James S Kalus of the Henry Ford Hospital, Detroit, conducted a study which found that healthy adults who drank two cans of an energy drink a day for a week experienced an 11% increase in their average heart rate and a 7% increase in their blood pressure – bad news!

How does caffeine inprove your athletic ability?

“Caffeine stimulates the central nervous system,” says sports scientist Gareth Nicholas. “This reduces your perception of effort, meaning you can work harder and improve your performance without feeling the negative effects.”

Make sure you drink plenty of water as caffeine can cause dehydration. Always check the ingredients and watch your level of intake: energy drinks are great for a short-term fix but can be dangerous if consumed to excess, especially when mixed with alcohol. Moderate intake is safe for the majority of people.

(Men's Health)