Przegląd Geograficzny (2023) vol. 95, iss. 3

Seasonal Variations in Melatonin Secretory Rhythms in High-, Middle-, and Low-Latitude Regions

Takeshi Morita, Krzysztof Błażejczyk

Przegląd Geograficzny (2023) vol. 95, iss. 3, pp. 225-235 | Full text
doi: https://doi.org/10.7163/PrzG.2023.3.1

Abstract

This study aims to measure the daily melatonin secretory rhythms of people living in high-, mid-, and low-latitude regions characterised by different day lengths and global solar-radiation conditions. In Poland, a high-latitude region, the amount of melatonin secretion is greater, with secretion occurring earlier (exemplifying phase advance). On the other hand, in Vietnam, a low-latitude region, the level is lower and occurs later (phase delay). Japan, a mid-latitude region, shows behaviour intermediate between these two. Melatonin secretory rhythm in Vietnam is closely related to Day length and Global Solar Radiation, though no such relationship is observed in Poland or Japan, making it necessary for other factors to be considered. The results of this study have important implications considering the impacts of light pollution and lighting-related conditions of modern life.

Keywords: melatonin, chronobiology, circadian rhythm, seasonality, lighting conditions, latitude.

Takeshi Morita [morita@fwu.ac.jp], Fukuoka Women’s University, Faculty of Human Environmental Science; Kyoto University, Graduate School of Medicine
Krzysztof Błażejczyk [k.blaz@twarda.pan.pl], Institute of Geography and Spatial Organization Polish Academy of Sciences, Twarda 51/55, 00‑818 Warszawa, Poland

Citation

APA: Morita, T., & Błażejczyk, K. (2023). Seasonal Variations in Melatonin Secretory Rhythms in High-, Middle-, and Low-Latitude Regions. Przegląd Geograficzny, 95(3), 225-235. https://doi.org/10.7163/PrzG.2023.3.1

MLA: Morita, Takeshi and Błażejczyk, Krzysztof. "Seasonal Variations in Melatonin Secretory Rhythms in High-, Middle-, and Low-Latitude Regions". Przegląd Geograficzny, vol. 95, no. 3, 2023, pp. 225-235. https://doi.org/10.7163/PrzG.2023.3.1

Chicago: Morita, Takeshi and Błażejczyk, Krzysztof. "Seasonal Variations in Melatonin Secretory Rhythms in High-, Middle-, and Low-Latitude Regions". Przegląd Geograficzny 95, no. 3 (2023): 225-235. https://doi.org/10.7163/PrzG.2023.3.1

Harvard: Morita, T., & Błażejczyk, K. 2023. "Seasonal Variations in Melatonin Secretory Rhythms in High-, Middle-, and Low-Latitude Regions". Przegląd Geograficzny, vol. 95, no. 3, pp. 225-235. https://doi.org/10.7163/PrzG.2023.3.1