Oct 04, 2014 05:40 AM EDT By Staff Reporter, UniversityHerald Reporter

Energy drinks increase the frequency of insomnia, nervousness and the level of stimulation in athletes, according to a Camilo José Cela University (UCJC) study. The negative effects are observed immediately in the hours following the intake of the drinks.

The consumption of energy drinks by athletes has increased in recent years. Over 50 percent consume them during training and even before competitions.

Energy drinks mainly comprise of carbohydrates, caffeine, taurine and B vitamins. Contradicting their trade name, energy drinks do not actually provide more energy than other soft drinks (~40 kcal/100 ml of product) and generate a significant effect on physical or cognitive performance. But researchers said that they do have an 'energising' effect related to the stimulation provided by caffeine.

In the study, sportsmen (football, basketball, rugby, volleyball, tennis, and hockey), climbers and swimmers drank either three cans of energy drink or an energy drink placebo before a sports competition.

Researchers measured the athlete's sporting performance through GPS devices to determine their distance and speed. They also used dynamometers and potentiometers to measure their muscle performance.

Researchers found that energy drinks enhanced sports performance between three to seven percent. It helped athletes run further in team competitions at higher intensities.

"Athletes felt they had more strength, power and resistance with the energy drink than with the placebo drink. Energy drinks increase jump height for basketball players, muscle force and power for climbers and trained individuals, swimming speed for sprinter swimmers, hit force and accuracy for volleyball players and the number of points scored in tennis," Juan Del Coso Garrigós, one of the authors and in charge of the Exercise Physiology Laboratory at the UCJC, in a press release.

Researchers also surveyed athletes about their feelings after consuming energy drinks and compared its side effects with the placebo drink. They found that the consumption triggered side effects associated with other caffeinated drinks.

"Caffeinated energy drinks are a commercial product that can significantly increase sporting performance in many sports activities," said Del Coso. "The increase in their consumption is probably driven by the hard advertising campaigns of energy drink companies related to sports sponsorships".

The finding is published in the British Journal of Nutrition.                                

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