Energy drinks increase sports performance – and insomnia and nervousness, says study
The research, published in the British Journal of Nutrition, looked at the impact of consumption of three cans of energy drink for competitive footballers, climbers, swimmers and basketball, rugby, volleyball, tennis and hockey players before a sports session.
Researchers from the Camilo José Cela University in Madrid gave 90 experienced and low-caffeine-consuming athletes (53 male and 37 female) either 3 mg/kg of caffeine in the form of an energy drink, or a placebo caffeine-free equivalent an hour before a training session.
The researchers also used a GPS system to measure the performance by speed and distance, as well as dynamometers and potentiometers - - devices for measuring force - to track the muscle performance during some of the sports.
Other effects were measured with a questionnaire, which revealed an increase in self-perceived muscle power during exercise for those who drank the energy drink compared to those who were given the placebo.
However the caffeine drink also increased the prevalence of side effects. No differences were observed in men and women across the two groups and for both positive and adverse effects.
Higher, faster, stronger
The athletes consuming the energy drinks ran further in team competitions, especially at higher intensities, the researchers said.
For basketball players energy drinks increased jump height, while muscle force and power increased for climbers and those training, swimming speed for sprinter swimmers, hit force and accuracy for volleyball and the number of points scored for tennis players.
The questionnaire revealed that athletes felt they had more strength, power and resistance with the energy drink than with the placebo drink.
"However, the energy drinks increased the frequency of insomnia, nervousness and the level of stimulation in the hours following the competition,” Juan Del Coso, one of the researchers behind the study, said.
He said these side effects were similar to those sometimes experienced with other caffeinated drinks.
"Caffeinated energy drinks are a commercial product that can significantly increase sporting performance in many sports activities," Del Coso said. "The increase in their consumption is probably driven by the hard advertising campaigns of energy drink companies related to sports sponsorships."
Source: British Journal of Nutrition
Published online ahead of print, DOI: http://dx.doi.org/10.1017/S0007114514002189
'The use of energy drinks in sport: perceived ergogenicity and side effects in male and female athletes'
Authors: J. J. Salinero, B. Lara, J. Abian-Vicen, C. Gonzalez-Millán, F. Areces, C. Gallo-Salazar, D. Ruiz-Vicente and J. Del Coso