Hormonal balance, anovulatory cycles and luteal phase deficiency: exploring relationships between hematological variables, sex hormones and VO2max in athletes

The menstrual cycle may affect physical fitness in female athletes, but the evidence remains unclear. Hormones such as estrogen and progesterone fluctuate during different phases of the menstrual cycle and can influence performance. However, menstrual bleeding does not always indicate ovulation, and many women may not realize they are not ovulating or producing eggs. In our study, we analyzed 27 female athletes aged 18-40 with regular cycles, measuring cardiorespiratory fitness V̇O2max and hormone levels across the menstrual cycle. We found that 26% of participants were either not producing eggs or their womb lining was not thick enough to support a healthy cycle. These women showed consistent V̇O2max levels throughout the cycle, while those with ovulatory cycles** - where an egg is released - **exhibited variations in performance. These findings highlight the importance of monitoring ovulation, not just bleeding, to understand how the menstrual cycle impacts fitness and health. Tailoring training to menstrual phases could optimize performance for women with ovulatory cycles.