Effects of forest bathing (shinrin-yoku) on serotonin in serum, depressive symptoms and subjective sleep quality in middle-aged males.

"Declaration Ethics approval and consent to participateThis study was conducted under the Declaration of Helsinki. The Ethics Committees of the Nippon Medical School (No. 30-11) on January 16, 2019 and Nagano Prefectural Kiso Hospital (No. 30-2) on January 30, 2019 approved this study. Written informed consent was obtained from all subjects after a full explanation of the study procedures. Consent for publicationNot applicable. Availability of data and materialThe datasets used and analyzed during the current study are available on reasonable request to the corresponding author. Competing interestsThe authors declare that they have no competing interests. FundingThis study was conducted as a research project from the Vehicle Racing Commemorative Foundation of Japan (2019). Authors’ contributionsQing Li conceived and designed the study and contributed to data acquisition, interpretation of results, and manuscript preparation. Hiroko Ochiai, Toshiya Ochiai, and Norimasa Takayama conducted data acquisition. Takashi Miura and Shigeyoshi Kumeda contributed to preparation of the experimental sites and cooperated with data acquisition. Michiko Imai conceived the study and participated in the interpretation of results. Yoichiro Aoyagi participated in the interpretation of results. All authors have read and approved the final version submitted for publication. AcknowledgmentsThis study was conducted as a research project from the Vehicle Racing Commemorative Foundation of Japan. We would like to acknowledge the participants of this Study. Authors’ informationQing Li, MD, PhD, clinical professor, Department of Rehabilitation Medicine, Graduate School of Medicine, Nippon Medical School, Tokyo, JapanHiroko Ochiai, MD, PhD, Department of Plastic and Reconstructive Surgery, Laboratory of Regenerative Medicine, Division of Hearing and Balance Disorder, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical CenterToshiya Ochiai, Forest Baubiologie Studio Inc., Tokyo, JapanNorimasa Takayama, PhD, Forestry and Forest Products Research Institute, Forest Research and Management Organization, Tsukuba, JapanShigeyoshi Kumeda, MD, PhD, Nagano Prefectural Kiso Hospital, Nagano prefecture, JapanTakashi Miura, Agematsu Town Office Industry & Tourism Department, Nagano prefecture, JapanYoichiro Aoyagi, MD, PhD, professor, Department of Rehabilitation Medicine, Graduate School of Medicine, Nippon Medical School, Tokyo, JapanMichiko Imai, MD, PhD, the president of INFOM (International Society of Nature and Forest Medicine), Tokyo, Japan Competing interests The authors declare that they have no competing interests."

"Funding This study was conducted as a research project from the Vehicle Racing Commemorative Foundation of Japan (2019)."