Changes in urinary serotonin levels during a kendo competition involving mental stress: a study on top-level male Japanese university kendo athletes

BACKGROUND: An athletic competition involves high levels of mental stress, including anxiety, which hinders athletes from maximizing their performance.METHODS: Seven healthy men who belonged to a kendo club at a national physical education college in Japan were included in this study. The urinary excretion of serotonin (5-hydroxytryptamine; 5-HT), which is associated with anxiety, was measured during training and competition in top-level male Japanese university kendo athletes. Urinary 5-HT levels were evaluated by repeated measures two-way analysis of variance (ANOVA), with factors including time (pre and post) and condition (training and competition).RESULTS: The analysis of the hourly urinary 5-HT levels during training and competition showed the main effect of time (P<0.05) and condition (P<0.05). However, this effect was limited by the significant interaction between time and condition (P<0.001). Thus, the simple main effect of time was re-evaluated, resulting in significantly lower urinary 5-HT levels precompetition than that postcompetition (P<0.001). Furthermore, the analysis of the simple main effect of condition showed significantly lower urinary 5-HT levels precompetition than that pretraining (P<0.001). Moreover, the urinary 5-HT levels on the day of kendo competition were significantly lower than on the day of kendo training (P<0.001).CONCLUSIONS: The neural activity of 5-HT decreased precompetition, indicating a high level of anxiety in top-level male Japanese university kendo athletes.