Words: Anna Beck                                                                                            Photos: Phil Gale
 
Ladies, can you relate to this?
 
The preparation had been going well, the numbers were solid and the skills were honed. The nutrition was sorted, the plan was made and you’re ready to go.
 
The starting gun goes off… and you started going backwards.
 
Have you ever had that feeling, hurting from the gun and the inability to ‘get going’? You’re hot and bothered and plagued by what seems like dehydration, despite your careful attention to event pre-hydration and watching your fluid intake mid race.
 
It seems, in a sport with as many variables as mountain biking, that to pin a day like that down to hormones may be a bit of a stretch but hormones can often be linked to both good and bad days on the bike.


 
Unpacking the menstrual cycle
 
The average menstrual cycle is 28 days long but can range from 21 to 35 days in healthy people, and consists of two distinct phases; day 1–14 (day one starting on the first day of your period) is called the follicular phase, and days 15–28 are called the luteal phase, with the benchmark occurrence of ovulation being the division between the two.
 
The early part of the follicular phase, during your period, is a low-hormone phase. In this respect, during the first 5–6 days of your cycle you are physiologically most similar to a man. At this point, mid follicular cycle, your levels of FSH (follicle-stimulating hormone) increase to stimulate
ovulation. At around day 12, there is a surge in both oestrogen and LH (lutenizing hormone) to facilitate ovulation and egg release. A small dip in oestrogen takes us to the luteal phase.
 
Through the luteal phase, oestrogen and progesterone rise to prepare in case of pregnancy, peaking at about day 23 (or 5 days prior to your period). From here there is a decline in both hormones leading to many of the symptoms described as PMS, and starting the cycle again.