Comparison of urinary serotonin levels among 3-6 year-old children before and after rhythmic exercises ; The effects of age, fatigue, season and sunshine

Abstract

We have previously demonstrated that rhythmic exercises such as Zen abdominal breathing, gum-chewing, hula dancing and so on caused an increased serotonin(5-HT) in adult human. In present study, we evaluated change in urinary 5-HT in 3-6y.o children before and after rhythmic exercise program (REP) including zigzag run, jumping rope, vaulting box, climbing bar, doing horizontal bar and overhead ladder etc. REP elicited a significant increase in urinary 5-HT in senior (5-6y.o.) children and smaller increase in junior (4-5y.o.) children. However mean basal level of urinary 5HT obtained before REP in senior children was lower than that of junior children. We further evaluated those modulating factors of season and fatigue which would affect REP-induced changes in urinary 5-HT. Fatigue, elicited by a whole day excursion, caused an attenuation of the REP-induced increase in urinary 5-HT. A seasonal effects were examined on a day in summer(27°C), winter(9°C) or spring(12°C). The mean basal urinary 5-HT obtained on the summer day was significantly higher than those on the winter day or spring day. REP on sunny day in winter caused greater increase in urinary 5-HT than that on cloudy day in winter. [J Physiol Sci. 2008;58 Suppl:S111]