2010 年 36 巻 12 号 p. 847-854
The purpose of this research was to clarify the effect of repeated administration of 2 kinds of energy drink,1 containing vitamins,taurine and caffeine (simple-type),and the other containing vitamins,taurine,caffeine and several botanical herb extracts (herb-type),on work performance using cognitively subjective and objective indicators.
The simple-type and herb-type drinks were given to 14 healthy young adults in a consecutive double-blind,randomized,2-period cross-over clinical trial.Participants took each energy drink once a day for five days during separate periods.Motivation,feeling of drowsiness,and general fatigue were evaluated on a subjective scale using a self-reported questionnaire both before and after administration.Other subjective evaluations were those based on the fatigue-visual analog scale (Fatigue-VAS) and multi-dimensional fatigue inventory-20 (MFI-20).As an objective measure,work performance was examined using the Kreapelin mental work test.
Compared to the simple-type drink,the herb-type drink achieved a significant reduction in drowsiness and significantly increased motivation based on the self-reported questionnaire results for the post-administration assessment.In the Kreapelin mental work test,the mean amount of work was significantly increased by both drinks.MFI-20 revealed significant decreases in 2 categories of physical fatigue and general fatigue due to the 2 drinks.The fatigue-VAS also indicated decreases but they were not statistically significant.
Both types of energy drink appeared to be effective in terms of subjective and objective indicators.Though the herb-type drink was found to be superior to the simple-type drink regarding subjective measures,there was no significant difference between the 2 regarding the objective measure.