Energy Drinks Increase Insomnia Among Athletes

Although energy drinks may improve athletic performance, they may also increase the risk for insomnia and nervousness.

Energy drinks may improve the performance of athletes, but at the cost of sleep loss, the results of a British study suggest.

The study, published online on September 12, 2014, in the British Journal of Nutrition, found that athletes who consumed energy drinks were more likely to develop insomnia and nervousness than those who abstained from the beverages.

The 4-year study analyzed the psycho-physiological changes and side effects associated with consuming excess amounts of caffeine from energy drinks. Male and female football, swim, basketball, rugby, volleyball, tennis, and hockey athletes were randomly assigned to consume an energy drink containing 3mg/kg of caffeine or a decaffeinated, placebo drink.

One hour after drinking the beverages, the athletes completed a training session in which their speed, distance, and other performance measures were recorded. The athletes also completed questionnaires about their perceived performance and any side effects they experienced.

When compared with those who drank the placebo beverage, those who consumed energy drinks noticed that their sports performance improved by 3% to 7%.

"[E]nergy 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,” said study author Juan Del Coso Garrigós, PhD, in a press release. "What is more, they ran further in team competitions, especially at higher intensities, which is related to sports performance."

In addition, the results indicated that athletes who were given caffeinated energy drinks reported feeling greater muscle power during the training session than those who drank the decaffeinated placebo beverage.

Although athletes who consumed energy drinks felt stronger during exercise, they reported more adverse side effects following the session. Energy drinkers more frequently reported insomnia, nervousness, and activeness after exercise than those in the placebo group. Both negative and positive side effects associated with the drinks were similar among men and women.

Despite the possibility of negative side effects, the use of energy drinks has dramatically increased over the last few years, particularly among athletes, the study authors noted.

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