Abstract
OBJECTIVES: This study investigated the effects of the menstrual cycle phases on cortisol levels before and after a maximal incremental exercise test in women with and without premenstrual syndrome (PMS). METHODS: Nineteen healthy, active and eumenorrheic women completed five maximal incremental exercise tests; three of those were performed at specific phases of the menstrual cycle (i.e., menses, follicular, and luteal). The participants were allocated into two groups according to the presence of PMS (n = 11) or absence of PMS (NO-PMS, n = 8). Samples of blood were collected before and after each experimental test. A three-way ANOVA was conducted to compare the differences between menstrual cycle phases (i.e., menses, follicular, and luteal), time (before and after) and groups (PMS and NO-PMS). RESULTS: The results demonstrated an alteration of cortisol across the menstrual cycle, with cortisol levels significantly (p < 0.05) higher during the follicular phase (mean = 11.0 μg/dL, CI95% = 9.1, 12.9) compared to the luteal phase (mean = 8.6 μg/dL, CI95% = 7.2, 10.4) in the PMS and NO-PMS groups. There was no difference (p > 0.05) in cortisol levels for groups or time. CONCLUSIONS: This study observed significant cortisol fluctuations across the menstrual cycle phases in women with and without PMS. Future studies should consider alternative maximal incremental test protocols and incorporate a more comprehensive hormonal profile to provide a deeper physiological understanding of this population.