Effects of caffeinated alcoholic beverages with low alcohol and high caffeine content on cognitive and motor functions.
OBJECTIVE: 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.
METHODS: 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.
RESULTS: 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.
CONCLUSIONS: CABs that contains a higher ratio of caffeine to alcohol did not counteract the motor function impairments induced by alcohol.