Influence of Menstrual Cycle Stages on Female Athletes

Influence of Menstrual Cycle Stages on Physical Fitness in Female Athletes

The influence of the menstrual cycle on women's sports performance is still uncertain. Research on this topic shows methodological biases. The aim of the study will be to determine whether the menstrual cycle affects women's physical fitness, measuring this in 3 differentiated stages of the cycle: the early follicular phase, late follicular phase, and luteal phase. For this purpose, a blood test will be carried out in each phase, with hormone determination (oestradiol and progesterone) and a haemogram to determine the existence of possible anemia. After the extraction and other complementary tests (measurement of vital signs, bioimpedance...) the woman will undergo 3 physical tests to compare the results in the 3 phases. A group of women taking hormonal contraception will also be included, performing the same interventions. To determine whether the woman is ovulating or not, urinary luteinizing hormone (LH) strips will be given to the women and they will have to take them from day 8 of the cycle. In addition, women will wear an accelerometer to monitor their daily activity and to be able to observe if there is an influence on this stage of the menstrual cycle.

Inclusion Criteria:

Inclusion criteria natural cycles group:

• Female sex
• Women between 18 and 40 years of age
• Women who are members of a federation and who compete in a sport doing at least 240 minutes of exercise per week.
• Women with regular menstrual cycles (between 23 and 38 days long).
• Women who have not taken hormonal contraceptives (HA) for 6 months or more.

Inclusion criteria artificial cycles group:

• Female sex
• Women between 18-40 years of age
• Women federated and competed in a sport doing at least 240 minutes of exercise per week.
• Long-term users of HA (minimum 6 months).

Exclusion Criteria:

Exclusion criteria group natural cycles:

• Refusal to participate in the study
• Sedentary women
• Women on HA currently or in the 6 months before the study
• Women with irregular menstrual cycles, less than 23 or more than 38 days in length
• Any existing metabolic disease or disorder
• Regular use of medications or dietary supplements that could affect the results
• Pregnancy or breastfeeding

Exclusion criteria artificial cycles group:

• Refusal to participate in the study
• Sedentary women
• Any existing metabolic disease or disorder
• Regular use of medications or dietary supplements that could affect the results
• Inability to manage contraception in a disciplined manner