Research

A possible connection between psychosomatic symptoms and daily rhythmicity in growth hormone secretion in healthy Japanese students

Mitsuo Nagane¹ , Kazunori Yoshimura² , Shu-Ichi Watanabe³ and Masahiko Nomura⁴

¹  Department of Educational Physiology, Chiba University, Chiba 263-8522, Japan

²  Department of Rehabilitation, Nihon Institute of Medical Science, Japan

³  Department of Physiology, Saitama Medical University, Japan

⁴  International Education and Training Center, Saitama Medical University, Japan

author email corresponding author email

Journal of Circadian Rhythms 2009, 7:10doi:10.1186/1740-3391-7-10

Published:	5 August 2009

Abstract

Background

Students suffering from psychosomatic symptoms, including drowsiness and feelings of melancholy, often have basic lifestyle problems. The aim of this study was to investigate whether psychosomatic complaints may be related to circadian dysfunction.

Methods

We examined 15 healthy students (4 men and 11 women) between 21 and 22 years old. To assess the presence of psychosomatic symptoms among the subjects, we developed a self-assessment psychosomatic complaints questionnaire consisting of five items pertaining to physical symptoms and five items concerning mental symptoms. The subjects rated their psychosomatic symptoms twice a day (08:00 and 20:00 h). We also assessed growth hormone secretion patterns by fluorescence enzyme immunoassay (FEIA). Salivary samples were collected from the subjects at home five times a day (20:00, 24:00, 04:00, 08:00, and 12:00 h) in Salivette tubes.

Results

The results indicated a relationship between the self-assessment scores and the salivary levels of growth hormone. Subjects with high self-assessment scores showed significant variability in growth hormone secretion over the day, whereas subjects with low self-assessment scores did not.

Conclusion

Psychosomatic symptoms may be associated with circadian dysfunction, as inferred from blunted rhythmicity in growth hormone secretion.