October 15, 2020 6 min read
Jennie Haire is a registered Nutritionist and holds an MSc and a BSc in Science from University College Dublin.
We all know that there are times throughout our menstrual cycle that we just feel a bit ‘bleughh’ and others where we are feeling like superwoman! There’s good science to explain why everything from your mood, to cravings, to your performance in the gym varies over the course of the month - and it’s all down to our female hormones; oestrogen & progesterone.
A textbook example of the female cycle is 28 days, however, this varies from woman to woman and recent research shows that a healthy cycle can be anywhere up to 35-40 days. For the purpose of outlining the different phases of the cycle in this series, I will use a typical 28 day cycle as an example.
It’s worth noting that if you are on any form of hormonal contraception such as the pill or the bar, your natural hormones are flatlined and you will not experience the hormonal fluctuations outlined below.
Let's have a good look at what’s going on over the course of the month:
Your cycle begins on day 1 of your period and lasts approximately 5 days. Oestrogen and progesterone are at their lowest and for this reason you may notice a drop in your overall mood. The drop in hormones stimulates the shedding of the uterine lining (your period).
Some women feel menstrual cycle symptoms such as cramps and bloating. Feeling fatigued in this phase is very normal so it’s important to listen to your body and only do what feels comfortable from a training perspective. Research has shown that white cell count is lower in this phase of your cycle - to compensate for this, aim to fuel your body with nutrient dense foods, reduce refined sugar and prioritise sleep to reduce risk of illness or injury.
From a nutrition perspective, women have a heightened sensitivity to insulin in the first half of their cycle (day 1 - 14) meaning that they havean increased ability to to utilise carbohydrates as fuel. Have you ever noticed that you crave carbohydrate rich foods during your period? Or chocolate specifically? Well, it’s not in your head, this is your body’s way of asking you to fuel it with carbohydrates! Recent research has also been able to link chocolate cravings to your body’s desire for magnesium-rich foods! Dark chocolate is an excellent source of magnesium - so don’t fight it, allow yourself a few squares! Try and opt for good quality dark chocolate that has a cacao content of at least 70%. During menstruation your body actually needs ~ 150 calories more than normal and the reason for most women’s increased appetite around this time.
This is still the low hormone phase however, oestrogen continues to rise over the course of this phase until it reaches its peak at ovulation (day 14). In the small percentage of studies that do include female participants, they are usually studied at this stage in the cycle as this is when our physiology is most similar to that of males.
Increasing oestrogen levels are associated with a release of feel-good hormones so you should notice your mood being energetic and positive in this phase!Oestrogen is an anabolic hormone meaning high oestrogen levels are conducive to building muscle.
Research demonstrates the benefit of including the majority of strength and high-impact cardiovascular training in this phase as we are much more capable of hitting high intensities. In a recent study participants who performed most of their strength training in the follicular phase and significantly fewer strength sessions in the luteal phase had higher lean body-mass compared to the female participants who performed the majority of strength training in the luteal phase. Women also have a heightened ability to recover from intense sessions in the follicular phase.
Similar to during menstruation, carbohydrates are the preferred fuel source in the follicular phase. Opt for good quality complex carbohydrates such as potatoes, brown rice and whole grains. Females have a shorter recovery window than males; try to get ~25g of highly bioavailable protein on board as soon as possible after training; greek yoghurt and whey protein are great options to have on hand post-workout.
Ovulation itself typically happens around day 14 but the characteristics of the phase are true for ~ 4 days.
Ovulation is the most important part of the female cycle, regardless of whether you are trying to conceive or not. Ovulation is the way our body produces progesterone.Progesterone balances oestrogen and has a calming, anti-anxiety effect on the body, alongside an array of other health benefits from bone, skin and heart health.
Oestrogen levels start to decline as ovulation occurs but then both oestrogen and progesterone start to rise and remain high for the duration of the cycle. Basal body temperature rises after ovulation, this is one of the key indicators that ovulation has occurred. Testosterone is also at its highest during ovulation resulting in a higher sex drive.
Most women feel energetic and confident around the time of ovulation but sometimes the change in hormone levels can impact mood and some women start to feel more lethargic.All types of training are good in this phase. If energy levels drop, lower-impact exercise such as pilates, flexibility work and light jogging are very beneficial. Exercise has been shown to have an anti-inflammatory effect on the body which has a positive impact on PMS symptoms that can start to present in the run up to menstruation.
From a nutrition perspective, fat takes over at this point in the cycle as the preferred fuel source and blood sugar levels are more likely to be unstable. It is important to include good quality protein sources at every meal to help balance blood sugars. New research shows that the current protein guideline of 1.2g per kg of body weight is too low for females, with requirements actually being closer to 2-2.2g per kg of body weight. Adequate protein intake is of key importance for women at every life stage from adolescence to menopause.
Oestrogen & progesterone remain high for the duration of the luteal phase and then begin to decline in the lead up to menstruation. The decrease in hormone levels can impact your ability to get quality sleep, your basal body temperature is also raised which can negatively affect sleep.
When it comes to training in the luteal phase it is important to listen to how your body is feeling as some women can feel ‘flatter’ and more fatigued at this point in the cycle -instead of forcing yourself to make that gym class try opting for a lower-impact forms of exercise such as walking, pilates and yoga. The decreased hormone levels trigger an inflammatory response in the body, for this reason it is good to avoid intense cardio and resistance training as this places additional stress on the body. Lower-impact exercise as mentioned above are effective ways of keeping cortisol levels in the body low (high cortisol levels trigger fat storage - not what we want!). Progesterone is also a catabolic hormone that interferes with our ability to build muscle and recover in this phase so this should also be considered when choosing your workouts in the luteal phase.
Focus on regularly fuelling your body with balanced meals that include complex carbohydrates, healthy fats and protein to help keep blood sugars balanced and cravings at bay. Eating foods rich in vitamin D, magnesium, zinc and fish oils have also been shown to help PMS symptoms.
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