the follicular phase , causes body temperature to increase to prepare for the fertilisation of an egg . If fertilisation does not occur , both oestrogen and progesterone levels decrease abruptly in the second half of the luteal phase .
FIGURE 1 : Changes in oestrogen and progesterone across the menstrual cycle
fractures . Female runners with irregular or absent menstruation have significantly lower bone density than runners with regular menstruation and even compared to nonathletes , particularly at the lumbar spine .
An irregular menstrual cycle makes planning the training more complicated than when not having a menstrual cycle at all , because you can ’ t predict the months that will have a normal cycle and the months that won ’ t , unless the cycle is ‘ regularly irregular ’ and therefore predictable . If the cycle is ‘ irregularly irregular ’, you need to plan the training month-to-month or even week-to-week .
With no menstrual cycle , women can train without consideration to the hormonal environment , since oestrogen and progesterone won ’ t fluctuate throughout the month . It ’ s perfectly okay to run a lot without a menstrual cycle . However , in the face of a lack of boneprotecting oestrogen , you need to take extra precaution in regard to your clients ’ bone health , especially if they run a lot . Meticulously planning the training so that they avoid rapid increases in volume and intensity , calcium and vitamin D supplements , oral contraception to provide oestrogen , and intense strength training to increase bone density can all help mitigate the risk for bone injuries .
Training
Menstrual cycle fluctuations in oestrogen and progesterone have several effects that concern a female runner , including body temperature ( which increases with increased progesterone ), metabolism ( which is shifted toward a greater reliance on fat with oestrogen ), breathing ( which increases from increased progesterone ), and bone density ( which decreases with reduced oestrogen ).=
Menstrual irregularities
In a perfect physiological environment , the menstrual cycle will occur every month and always be the same duration . But that doesn ’ t always happen , especially among women who train with high volumes and high intensities and have a low percentage of body fat . They often experience irregular or even absent menstrual cycles , which reduce oestrogen levels .
In response to heavy training , the first change in the menstrual cycle is a shortening of the luteal phase , followed by cycles without ovulation and , finally , cessation of menses , called amenorrhea , which is defined as having three or fewer periods per year , and results in constantly low levels of oestrogen and progesterone . An amenorrheic runner experiences an oestrogen-deficient state similar to that of a postmenopausal woman .
Consuming fewer calories than what is burned , rather than the stress of exercise itself , can be responsible for the loss of the menstrual cycle . Consuming enough calories to replace the calories burned from running can prevent amenorrhea . Therefore , if your clients run a lot , they need to increase the number of calories they consume throughout the day to keep up with the large number of calories they burn by running .
Any disruption to the menstrual cycle can cause a decrease in bone density , increasing the risk for osteoporosis and stress
Your female running client ’ s training program must always be open to change , moving workouts around based on the menstrual cycle ’ s hormonal fluctuations and on how she feels . However , few female runners or coaches take the menstrual cycle into consideration when planning training , in regard to both optimising the training and injury prevention . They tend to spend too much time working in their training rather than working on their training .
Working on the training means developing a system of training that is specific to female runners . It means developing a system that works . The menstrual cycle is that system . But , guess what ? You don ’ t need to create the system yourself . The menstrual cycle already exists . The system is already made for you ! You only need to listen to it and follow it .
Before trying to get fancy or sophisticated with menstrual cyclebased training , the simplest ( and most insightful ) way to implement the system is to keep track of how your clients feel and perform during their normal training . Write down each day of their menstrual cycle , the data from their workouts , and how they felt during each run . After a few months of documentation , you ’ ll likely notice a
THE QUICK READ
• Oestrogen increases reliance on fat , which makes females suited for endurance
• The best time of the month to push endurance training is when oestrogen is high
• The worst time of the month for endurance performance is when progesterone is high and during period
• Congregate the hard endurance training during the oestrogendominant follicular phase of the menstrual cycle
• Be flexible with your female client ’ s training ; don ’ t think you must stick to a strict plan .
24 | NETWORK SPRING 2021