薬理と治療

Abstract

Objective　This study evaluated the effects of drinking green tea and roasted green tea（hojicha） on task performance and subjective evaluations of fatigue, stress, mental workload, and flow in a simulated situation. Methods　We conducted a crossover study of 20 healthy male participants. First, the participants repeated 5–min mental arithmetic tasks three times after ingesting plain hot water. Next, after ingesting either green tea or hojicha, they performed mental arithmetic tasks again three times for 5 min. The same experiment was repeated on another day, exchanging which participants received green tea vs. hojicha. Before and after the experiment, participants were asked to answer a questionnaire regarding their fatigue feelings and stress symptoms. After each task, they were asked to evaluate their subjective mental workload and flow states. They were also asked about their perception of the drink using the semantic differential method. Results　Intake of green tea and hojicha suppressed sleepiness. Also, improvements in some task performance indices were observed with green tea and hojicha intake compared to that of hot water. In addition, hojicha intake was found to have an inhibitory effect on negative feelings, such as time pressure. Conclusions　It is suggested that the task performances of mental arithmetic task including time pressure were improved by ingesting green tea or hojicha before and after the tasks. Arousal level might be maintained throughout the tea sessions. Furthermore, negative mood such as time pressure was suppressed by hojicha intake.（Jpn Pharmacol Ther 2023；51：1377‒88）