tailieunhanh - Báo cáo y học: "Effects of evening light conditions on salivary melatonin of Japanese junior high school students"

Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học Wertheim cung cấp cho các bạn kiến thức về ngành y đề tài: Effects of evening light conditions on salivary melatonin of Japanese junior high school students. | Journal of Circadian Rhythms BioMed Central Research Open Access Effects of evening light conditions on salivary melatonin of Japanese junior high school students Tetsuo Harada Address Laboratory of Environmental Physiology Faculty of Education Kochi University Kochi 780-8520 Japan Email Tetsuo Harada - haratets@ Corresponding author Published II August 2004 Received 02 April 2004 Journal of Circadian Rhythms 2004 2 4 doi 1740-3391-2-4 Accepted 1 1 August 2004 This article is available from http content 2 1 4 2004 Harada licensee BioMed Central Ltd. This is an open-access article distributed under the terms of the Creative Commons Attribution License http licenses by which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. Abstract Background In a previous study when adult subjects were exposed to a level of 400 lux light for more than 30 min or a level of 300 lux light for more than 2 hours salivary melatonin concentration during the night dropped lower than when the subjects were exposed to dim illumination. It was suggested that such light exposure in adolescents or children during the first half of subjective night in normal life might decrease the melatonin level and prevent the falling into sleep. However there has been no actual study on the effects of light exposure in adolescents. Methods Effects of exposure to the bright light 2000 lux from fluorescent light bulbs during a period of three hours from 19 30 to 22 30 in one evening were examined on evening salivary melatonin concentrations from 19 45 to 23 40. The control group was exposed to dim light 60 lux during these three hours. Both the dim light control group DLCG and the bright light experimental group BLEG consisted of two female and three male adolescent participants aged 14-15 y. Results The salivary melatonin level increased rapidly from pg ml at 21 45 to