Abstract

Background The aim is to provide normative data on oxytocin, and its seasonality in users and non-users of Oral Contraceptives (OC) in physically active women. Further, to elucidate the relationship between Oxytocin and Profile of Mood States (POMS) for further research to see if Oxytocin can be used as an additional diagnostic marker to detect overreaching/overtraining syndrome or other stress disorders. Methods Forty-eight women (18-35 years old), 19 with and 29 without OC use, physically active at least 3 times a week at > 13 on the Borg RPE scale. Thirty-three subjects completed the study, 15 with and 18 without OC use. The number of hours from sunrise to sunset averaged 10 h during the autumn, 6 h during the winter, and 15 h during the spring. Once a month, blood samples were taken, weight and the day of menstrual cycle was documented, the POMS questionnaire was filled out as well as a personal daily logbook recording exercise type, duration, and intensity. To evaluate seasonal variations in Oxytocin and Global POMS, repeated measures analysis of variance was used. Results A significant seasonal variation in Oxytocin levels within the groups with and without OC respectively and significant differences in Oxytocin levels between the groups at diverse seasons were found. No significant difference in seasonal variation of Global POMS within the groups and no significant differences in levels of Global POMS between the groups with and without OC were seen. Furthermore, no clear relationship between Oxytocin, Global POMS scores, and hours of daylight respectively were detected. Conclusions Due to seasonality, impact of OC use on oxytocin levels, methodological considerations, and no convincing relationship to Global POMS, oxytocin is not suggested to be an optimal, diagnostic marker alone or in combination with others to detect overreaching and overtraining syndrome in physically active women.

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