Int J Sports Physiol Perform. 2021 Mar 1;16(3):375-381. doi: 10.1123/ijspp.2020-0038. Epub 2020 Oct 1.
The influence of female sex hormones on body fluid regulation and metabolism homeostasis has been widely studied. However, it remains unclear whether hormone fluctuations throughout the menstrual cycle (MC) and with oral contraceptive (OC) use affect body composition (BC). Thus, the aim of this study was to investigate BC over the MC and OC cycle in well-trained females.
A total of 52 eumenorrheic and 33 monophasic OC-taking well-trained females participated in this study. Several BC variables were measured through bioelectrical impedance analysis 3 times in the eumenorrheic group (early follicular phase, late follicular phase, and midluteal phase) and on 2 occasions in the OC group (withdrawal phase and active pill phase).
Mixed linear model tests reported no significant differences in the BC variables (body weight, body mass index, basal metabolism, fat mass, fat-free mass, and total body water) between the MC phases or between the OC phases (P > .05 for all comparisons). Trivial and small effect sizes were found for all BC variables when comparing the MC phases in eumenorrheic females, as well as for the OC cycle phases.
According to the results, sex hormone fluctuations throughout the menstrual and OC cycle do not influence BC variables measured by bioelectrical impedance in well-trained females. Therefore, it seems that bioimpedance analysis can be conducted at any moment of the cycle, both for eumenorrheic women and women using OC.
女性性激素对体液调节和代谢稳态的影响已得到广泛研究。然而，激素在整个月经周期（MC）中的波动以及口服避孕药（OC）的使用是否会影响身体成分（BC）仍不清楚。因此，本研究旨在调查在训练有素的女性中整个 MC 和 OC 周期的 BC 变化。
共有 52 名月经正常和 33 名服用单相 OC 的训练有素的女性参加了这项研究。通过生物电阻抗分析在月经正常组中 3 次测量（卵泡早期、卵泡晚期和黄体中期）和 OC 组中 2 次测量（停药期和活性药丸期），共测量了几个 BC 变量。
混合线性模型测试报告，BC 变量（体重、体重指数、基础代谢、脂肪量、去脂体重和总体液）在 MC 期之间或 OC 期之间无显著差异（所有比较的 P >.05）。在月经正常的女性中比较 MC 期以及在比较 OC 周期期时，所有 BC 变量的差异都很小，且效应大小也很小。
根据结果，整个月经和 OC 周期中性激素的波动不会影响生物电阻抗分析测量的训练有素的女性的 BC 变量。因此，似乎可以在周期的任何时候进行生物阻抗分析，无论是月经正常的女性还是服用 OC 的女性。
