Guisado-Cuadrado, IsabelRomero-Parra, NuriaElliott-Sale, Kirsty J.Sale, CraigDíaz, Ángel E.Peinado, Ana B.2025-01-282025-01-282024-07-27Guisado-Cuadrado, I., Romero-Parra, N., Elliott-Sale, K.J. et al. Influence of Menstrual Cycle and Oral Contraceptive Phases on Bone (re)modelling Markers in Response to Interval Running. Calcif Tissue Int 115, 382–392 (2024). https://doi.org/10.1007/s00223-024-01259-40171-967Xhttps://hdl.handle.net/10115/66278To explore how sex hormone fluctuations may affect bone metabolism, this study aimed to examine P1NP and β-CTX-1 concentrations across the menstrual and oral contraceptive (OC) cycle phases in response to running. 17β-oestradiol, progesterone, P1NP and β-CTX-1 were analysed pre- and post-exercise in eight eumenorrheic females in the early-follicular, late-follicular, and mid-luteal phases, while 8 OC users were evaluated during the withdrawal and active pill-taking phases. The running protocol consisted of 8 × 3min treadmill runs at 85% of maximal aerobic speed. 17β-oestradiol concentrations (pg·ml-1) were lower in early-follicular (47.22 ± 39.75) compared to late-follicular (304.95 ± 235.85;p = < 0.001) and mid-luteal phase (165.56 ± 80.6;p = 0.003) and higher in withdrawal (46.51 ± 44.09) compared to active pill-taking phase (10.88 ± 11.24;p < 0.001). Progesterone (ng·ml-1) was higher in mid-luteal (13.214 ± 4.926) compared to early-follicular (0.521 ± 0.365; p < 0.001) and late-follicular phase (1.677 ± 2.586;p < 0.001). In eumenorrheic females, P1NP concentrations (ng·ml-1) were higher in late-follicular (69.97 ± 17.84) compared to early-follicular (60.96 ± 16.64;p = 0.006;) and mid-luteal phase (59.122 ± 11.77;p = 0.002). β-CTX-1 concentrations (ng·ml-1) were lower in mid-luteal (0.376 ± 0.098) compared to late-follicular (0.496 ± 0.166; p = 0.001) and early-follicular phase (0.452 ± 0.148; p = 0.039). OC users showed higher post-exercise P1NP concentrations in withdrawal phase (61.75 ± 8.32) compared to post-exercise in active pill-taking phase (45.45 ± 6;p < 0.001). Comparing hormonal profiles, post-exercise P1NP concentrations were higher in early-follicular (66.91 ± 16.26;p < 0.001), late-follicular (80.66 ± 16.35;p < 0.001) and mid-luteal phases (64.57 ± 9.68;p = 0.002) to active pill-taking phase. These findings underscore the importance of studying exercising females with different ovarian hormone profiles, as changes in sex hormone concentrations affect bone metabolism in response to running, showing a higher post-exercise P1NP concentrations in all menstrual cycle phases compared with active pill-taking phase of the OC cycle.enAttribution 4.0 Internationalhttp://creativecommons.org/licenses/by/4.0/Bone healthEnduranceEumenorrheicOestradiolP1NPβCTX-1.Article10.1007/s00223-024-01259-4info:eu-repo/semantics/openAccess