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The Menstrual Cycle

How does the menstrual cycle work:

The average menstrual cycle is about 28 days long. It can be shorter or way longer (especially if we are getting closer to menopause). The menstrual cycle is divided into two halftimes, which are each controlled by different hormone levels. 

Day 1 to 14 is the follicular phase or the low hormone phase. This phase will stimulate follicles for later ovulation. Follicles stimulating hormones will be released right at the beginning of this phase. Your ovaries will then steadily ramp up estrogen production until it surges and peaks around day 12, which will cause ovulation. Ovulation means that an egg is released and on its way from the ovary down the fallopian tube, where it can be fertilized. 

Day 15 to 28 is the luteal phase or the high hormone phase. Estrogen levels dip right after ovulation but will rise again to prepare for nesting in case the egg is fertilized. Progesterone will rise above the levels of estrogen to prepare the uterus for egg implementation. The hormone levels will peak about 5 days before menstruation. That’s the time where premenstrual syndrome (PMS) can occur. If the egg has not been fertilized, hormone levels will fall, menstrual bleeding will occur, and the menstrual cycle starts all over again.

How can we use this knowledge for sports performance?

The beginning of the cycle (the low hormone phase) starts with the first day of menstrual bleeding and is the most favorable time for performance from a hormonal point of view. Menstrual cramps will often distort a throughout good feeling, but the body is ready to perform, and it will feel easier compared to the high hormone phase. Studies show that women can make greater strength gains, produce more force, recovery faster and use carbs more efficient in the low hormone phase. This is where we need more research. Studies have shown that swimmers had their fastest times during the menstruation period and their slowest during the premenstrual period.


What does that mean for racing? 

The Vo2Max and lactate threshold does not seem to be influenced by the menstrual cycle, that means even during the high hormone phase women will be able to perform great. Studies have shown that in the high hormone phase reaction time, neuromuscular coordination and precise hand coordination are not as great as in the low hormone phase. On top of that thermoregulation, blood sugar levels and breathing rates are worse of during the high hormone phase. The point there is simple: hormones have the biggest influence on performance not menstruation itself.

You can race throughout your cycle, but if you have the chance to race during menstruation while keeping cramps at bay, you will have an hormonal advantage.


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