Hormonal health seems to be all the rage these days, with everyone harping on about cortisol and insulin and their influence upon your body’s (or client’s body’s) ability to drop fat. We know our hormones play a role in determining our body composition. We also know that females have more fluctuations in their hormones than men and that they are more influenced by these changes.
In this blog series, we are going explore the female reproductive cycle and it’s influence in depth through three parts:
Part I: Anatomy and physiology of the female reproductive system
Part II: Key hormones in each stage, and how this can influence your athlete
Part III: How we can best adapt our training and nutrition around these factors to optimise fat loss, even when our hormones seem to be working against us.
PART I: ANATOMY & PHYSIOLOGY OF THE FEMALE REPRODUCTIVE SYSTEM
Women are not just smaller, more aesthetically pleasing men – they are separate creatures, with a visibly different anatomy, and therefore physiology and hormonal profile – which inevitably leads to drastic differences in how their bodies respond to training, and their nutrient requirements. In order to understand how to manipulate and control these variables to optimise yours, or your client’s results, we first need to understand what is going on…
So, we’re taking a little journey back to 8th grade P.E class everybody!
Anatomy of the Female Reproductive System
Physiology of the Female Reproductive System
The vulva is the collective name for the external genitalia – specifically the mons veneris, labia majora, vestibule, perineum and clitoris. These are not shown in the above diagram
The vagina is the passage from the external genitalia to the internal genitalia. It extends from the vulva to the cervix, is the primary organ responsible for sexual intercourse, provides a passage for semen to travel, as well as a canal from which menstrual fluids can pass and babies are birthed.
The cervix connects the uterus to the vagina, and is located at the lower part of the uterus. It acts as a barrier between the vagina and uterus, controlling when and which substances can pass into or out of the uterus. Its’ walls produce a thick mucus which acts to ‘plug’ the cervix. Around ovulation, this mucus membrane becomes thinner to allow the passage of sperm to enter the uterus. In the event of pregnancy, this mucus becomes thick to protect the developing embryo during gestation.
The uterus is the hollow, muscular organ at the centre of the system. Its’ primary role is to accept a fertilized ovum and to nourish the developing embryo as it develops into a fetus and all the way through the gestation period until childbirth, when the thick muscular wall of the uterus produces the strong contractions known as labour. Upon conception, the uterus accepts and implants the fertilised egg within the cushiony endometrial wall, from which the fetus derives nourishment from blood vessels which develop exclusively for this purpose.
The endometrium refers to the epithelial layer of the uterus, along with its’ mucus membrane. This is where the fertilized ovum will be implanted should pregnancy to occur. This layer grows thicker with blood and blood vessels approaching ovulation, ready to accept a fertilized ovum. If this does not occur, this layer will shed forming a period.
The fallopian tubes are muscular tubes extending from and connecting the uterus to the ovaries. They act to nourish the developing ova, and help to transport the ripe ovum to the uterus.
The ovaries are a pair of small almond-shaped glands located to the upper left and right of the uterus. They produce the ova as well as the female sex hormones, such as Oestrogen and Progesterone. Once a female has reached puberty, the ovaries will release a single mature ovum once per month, usually taking turns– this process is called Ovulation. This process continues every month until Menopause.
PART II: KEY HORMONES IN EACH STAGE, AND HOW THEY AFFECT YOUR ATHLETE
Phases of the Female Reproductive Cycle
The female reproductive cycle is differentiated into two parts:
The Follicular Phase, which commences on Day 1 of Menses, (the start of her period) and lasts roughly 10-14 days, or until Ovulation occurs. This phase is characterised by the ovaries creating and then maturing a follicle to produce an ovum (egg).
The Luteal Phase is the second half of the cycle. Post Ovulation the follicle temporarily become a gland, known as the Corpus Luteum, which produces and secretes the hormone Progesterone to ‘hold’ the Endometrial Lining to the wall of the Uterus for implantation should the egg become fertilised. If fertilisation does not occur, a period will occur marking the return to the Follicular phase to begin a new cycle
Hormones of the Female Reproductive Cycle
The ovaries secrete oestrogen during the Follicular phase of the cycle. Oestrogen is the primary female reproductive hormone, and is also responsible for a female’s development during puberty. Oestrogen is also secreted in small amounts by the adrenal glands, liver and fat cells, and has some other roles in the body including healthy bone maintenance and cholesterol regulation. There are, in fact, three types of oestrogens: oestrone, oestradiol, oestriol. Oestrodial is the most abundant form in women of reproductive age. Oestrone is produced by the Uterus during pregnancy, and Oestriol is most abundant post-menopause.
Oestrogen directly opposes, and therefore decreases the activity of one of the major fat storing enzymes lipoprotein lipase (LPL). Essentially making the body less prone to fat storage and more prone to fat mobilisation. Oestrogen also opposes Cortisol, increases serotonin and endorphins in the brain, as well as the neurotransmitter acetylcholine, and improves leptin signalling. It also increases the production of bile in the Gall Bladder.
High levels of oestrogen can impair collagen synthesis and neuromuscular control, as well as increase weight gain, PMS symptoms, fibrocystic breasts and more.
This hormone is secreted by the Corpus Luteum during the Luteal phase. It acts as a protector and thickener of the endometrial lining. If pregnancy occurs, the ovaries and adrenal glands will continue to secrete Progesterone, to support embryonic growth, protect the endometrial wall and create a mucus membrane to seal the cervix.
Progesterone inhibits the action of oestrogen by suppressing the enzyme that promotes oestrogen synthesis. Additionally, progesterone enhances the function of serotonin receptors in the brain, acts an anti-inflammatory agent, is also involved in regulating the immune system and bone strengthening. Progesterone is the ‘protector’ hormone – it instills worry, anxiety and a heightened sense of awareness and attention to detail.
Follicle Stimulating Hormone (FSH)
This hormone is secreted by the Pituitary Gland in the brain. FSH stimulates the ovaries to produce eggs and mature a follicle for release, and is also involved in development during puberty.
Luteinising Hormone (LH)
This hormone is secreted in an acute manner by the pituitary gland and stimulates ovulation, and development of the Corpus Luteum, from the Follicle.
PART III – TRAINING & NUTRITIONAL CONSIDERATIONS
Having a basic understanding of the phases of the cycle, and their respective hormonal profiles, enables us to better understand the systems at play and how to manipulate the variables to better target the forces that may or may not be working to our advantage.
A dominant hormone characterizes each phase, and as hormones do, this affects many of the functions of the body.
The Follicular Phase is characterised by the hormonal profile of Oestrogen. During this phase, lasting from Day 1 of Menses to roughly Day 10-14, or whenever Ovulation occurs, Oestrogen production is ramped up and levels are on the rise. The other hormone that is dominant during this phase is FSH, however its’ affects are less noticeable. Characteristics of the Follicular Phase include stable body temperature, an increase in insulin sensitivity, suppression of appetite, metabolic function and rate, however these slowly begin to rise post-menses.
Energy and mood are boosted, females will feel more optimistic, sociable and outgoing and as well experiencing an increase in libido. This phase is also characterized by increased cognitive and neuromuscular function, motivation and focus. This is a good time for goal setting, starting new programs, planning for the future and making important decisions.
With an increase in energy production, mood and neuromuscular function, this period is optimal for phases of increasing load, periods of intensification and improving relative strength and power in motor patterns.
There is an increase in insulin sensitivity meaning that this is the time in her cycle when a female is most tolerant of carbohydrates, as the body is more primed for glycolysis, or the burning or glucose to produce energy.
Ironically, it is also a period of suppressed appetite, due to oestrogen influence on leptin signaling in the brain.
To support her hormonal health, during this phase a female should limit sodium intake, increase consumption of iron, B6 and B12 rich foods such as seafood, red meat, pork, chicken, eggs, broccoli and dark leafy greens such as spinach. It is also a good idea to supplement with a high quality pharmaceutical-grade fish oil.
The end of the follicular phase is marked with Ovulation, which has some pretty special characteristics and advantages of its’ own.
Ovulation can occur anywhere between days 10-14 of the cycle, and is characterized by a sharp rise in luteinising hormone and follicle stimulating hormone, which causes the follicle to release a mature egg and transform into the Corpus Luteum. It is the peak of her metabolic rate in her cycle as post ovulation metabolic processes begin to decrease slightly.
This is also the time when oestrogen levels peak in the body, increasing the pain threshold and force‐generation capability of your athlete, as well as a heightened state of confidence, mood, energy, brain function and optimism.
This is well and truly, peak week, and is the ideal time to ramp up intensity such as with a super accumulation phase, to attempt a new PR or Max Lift, and even learn new skills and motor patterns such as Olympic lifting, Muscle Ups, Turkish Get Ups and other advanced skills that are more demanding upon the nervous system.
The one drawback during this phase however, and is certainly important to note, is an increased risk of injury due to an increase in the hormone Relaxin which acts upon tendons and ligaments and “loosens” them slightly. It is even more critical during this time to ensure correct form is adhered to, to prevent injury.
The Luteal Phase lasts (or in many cases is endured!) from roughly days 15-28 or until day 1 of Menses. During the first half of the luteal phase progesterone begins to rise, whilst luteinizing hormone drops. Oestrogen drops post-ovulation, then begins to rise again pre-menses, before both progesterone and oestrogen drop to baseline triggering menstruation to begin.
The metabolic functions are on the increase again, with it the thermic effect of food and the body is more primed to burn fat during this phase.
However, insulin sensitivity is decreased, and cravings for salt, sugar, fat are common so diet should be carefully managed during this phase.
In the second half of the luteal phase, oestrogen dropping depletes serotonin and other happy neurochemicals in the brain leading to (further) moodiness, fatigue, depression, insomnia, and muscle aches. I often find clients who are heavily affected by PMS benefit from a deload week during this phase. It is also an optimal time to reset all volume targets and conduct reviews or assessments, as women are more analytical during this phase. Recovery and stress management are often crucial components during this phase, and the inclusion of activities such as massage, float tanks, yoga and walking can help to replete serotonin.
Some women experience pre-PMS symptoms such as irritabililty, tiredness, fogetfullnes, depression, being tongue-tied, brain fog, and a decrease in libido during this phase as well.
In terms of nutritional support, a reduction in calories and a shift in macros to a lower carbohydrate model can help to support the body’s fat loss mechanisms during this phase. Foods that should be limited include egg yolks, dairy, red meat, saturated fat, starch, sugar, sodium and alcohol. Women should also increase their intake of fibre to reduce bloating, turkey, and healthy fats. Some beneficial supplements during this phase include fish oil, thiamin, riboflavin, niacin, folate, B6 and B12 along with calcium, vitamin D, magnesium, and zinc.
When it comes to training during this phase, every female is different and every month can be too, so listen to your body and the signals it is sending you. Most women find moderating load and intensity with their resistence training can help to improve recoverability.
HIIT, or metabolic style workouts can be very beneficial for fat loss during this phase, if the intensity is tolerable. Alternatively, low intensity steady state cardio is a great option during this phase for both fat loss and restorative purposes.
Women do tend to have a harder journey with fat loss than most men do, because of this monthly influence of our cycle and hormonal fluctuations. In saying that, we can actually be better at burning fat when this information is taken into consideration and we understand our own bodies . Developing awareness around your own cycle, its’ symptoms and influence upon you, can dramatically help in the journey to being the best version of yourself you can be. Not only will you more likely be kinder to yourself during your Luteal phase and prioritise nutrition and recovery, but you will also know when to rev it up a notch and really push for more in the weights room and in life!