Effects of caffeinated alcoholic beverages with low alcohol and high caffeine content on cognitive and motor...

In Taiwan, caffeinated alcoholic beverages (CABs), with high caffeine but low alcohol concentrations compared to those sold in Western countries, are commonly consumed at work and have been associated with work-related injuries. However, the effects on cognitive and motor functions and self-perception have not been examined.

Twenty-eight healthy male volunteers (mean age: 32.6 ± 2.7) participated in the study. Each participant visited our laboratory 4 times at intervals of at least 1 week and was assigned to one of 4 trials in a counterbalanced order at each visit: placebo, alcohol, caffeinated energy drink, and CAB. They completed the subjective perception ratings, go/no-go tasks, Stroop color-word tests, Purdue pegboard tests, and the standardized field sobriety test. We used analysis of variance to examine the intraindividual differences in the performance.

Consuming alcohol of 0.23 g/kg typically consumed by Taiwanese CAB drinkers caused significant impairments in fine and crude motor functions; caffeine (1.5 mg/kg) did not antagonize these effects but led to an improvement in response speed in the go/no-go task. The subjective perceptions produced by alcohol were not masked by caffeine.

CABs that contains a higher ratio of caffeine to alcohol did not counteract the motor function impairments induced by alcohol.