Acute Effects of a Glucose Energy Drink on the Attentional Blink

There has been a dramatic rise is the consumption of energy drinks (e.g., Red Bull) in the past decade, particularly among college students. However, there has been little laboratory research to examine the acute effects of energy drinks on cognitive performance. The purpose of this study was to investigate the effects of a glucose energy drink on an attentional blink task and on subjective measures of mental fatigue and stimulation. Attentional blink is a phenomenon observed in rapid serial visual presentation. When a subject is presented with a sequence of visual stimuli in rapid succession at the same spatial location on a computer screen, a participant will often fail to detect a second salient target occurring in succession if it is presented between 200–500 ms after the first one. In this study, participants were randomly assigned to one of six dose conditions (energy drink doses of 1.8 ml/kg, 3.6 ml/kg, 5.4 ml/kg, and 7.2 ml/kg, a decaffeinated placebo beverage and a no drink condition). Participants completed the cognitive task and subjective measures both at baseline and at 30 min. after dose administration. The results indicated that the energy drink increased feelings of stimulation and decreased feelings of mental fatigue in a dose-dependent fashion. By contrast, only the lower doses of energy drink improved accuracy on the attentional blink task. The results are consistent with findings of other stimulant drugs that improvements in cognitive performance are not linear but instead look like an inverted-U shaped function