I was talking to a friend the other day about carb cycling for women, specifically regarding the luteal phase and the best workouts to do while in the luteal phase versus the remainder of the month. She asked me to elaborate, as this was something she had never heard before. She was aware of the 28 day cycle that women experience with their menstrual cycles, but had no idea there were phases inside the 28 day cycle.

For a monthly process that happens internally, it seems a little curious that we as women don’t know as much about our menstrual cycles, but not surprising based on the negative attribution society gives our periods. I hope to elaborate and explain the phases so you can learn the benefits, hormonally, mentally, and physically below.

I am going to take a second and shed a little shade on the patriarchy for not allowing women to feel positive curiosity towards their menstrual cycle. It is often still considered a “gross” or “unattractive” to even discuss menstrual cycles. I am here to declare that now, and in the new year, we will be moving forward in our society and eliminating the taboo regarding our periods.

They happen, and often, and health issues can occur, SO WE ARE GOING TO DISCUSS THEM.


The Phases of the Menstrual Cycle:

1) Menstrual or Bleeding Phase:

Day 1 of bleeding is considered day 1 of your cycle. Typically, a woman’s cycle is around 28 days long. This can vary women to women though.

The menstrual phase can be the most exhausting part of your month, as your body is on overdrive working to shed the inner lining of your uterus. This is the discharge and blood flow we experience during our period.  Often menstrual cramps occur as the uterine and your abdomen contracts and releases to help facilitate the passing of the blood and discharge. These cramps can be experienced before the menstrual phase, too, as the uterus prepares for the shedding. More on that below.

Because this phase tends to consume a lot of our energy, we subconsciously move towards introspection and time alone to restore and nourish our mental and physical health. This is not to say a women NEEDS to stay inside and restore during her bleeding phase; I know most women do not have the opportunity to do so.  Our body is signaling us to rest, however.

If you are looking for exercise activities that may be best for you during this phase, think gentle but brisk. VInyasa yoga or power walks can be restorative, and there is science behind using exercising as a way to eliminate cramps. This can also be beneficial and balancing to our mood during this phase (and all phases, really.)


2) Follicular Phase:

This phase overlaps with the Bleeding phase. Follicular phase initiates on day one but continues through until day thirteen. During this phase, the pituitary gland promotes egg growth by releasing FSH (Follicle Stimulating Hormone) to your ovaries. In the ovary, the egg growth continues while inside a follicle. The follicle must be strong enough and ready to release the egg, a process that takes thirteen days, hence the thirteen days of this cycle. Blood vessels and other soft tissue are now growing in the uterus due to more hormone secretion caused by the follicle. LH or “Luteinizing Hormone” is also produced at this time. LH basically tells the uterus to start thickening its lining that was once shed during the Menstrual/Bleeding phase.

The female body is naturally more insulin-sensitive in the follicular phase when estrogen levels are highest and progesterone levels are at their lowest. This means the body tolerates carbohydrates in these two weeks better than the rest of the time.

Since insulin sensitivity is at its highest in the first two weeks of the menstrual cycle, and carb intake is free to be at its highest because we tolerate them best, exercise can be more aerobic (long, moderate heart-rate-elevating cardio exercises). It is at this time that you can do your best high performance cardio training. Here you can challenge yourself with longer-term exercises that may be more “stressful” for your body, like long bike rides, tabata sprints, night-long dance sessions, and the like. It is at this time in your cycle that your body can handle the most aerobic stress.


3) Ovulatory Phase:

On the 14th day, the pituitary gland releases enough hormones to encourage the egg to be released. The egg is then ushered through the fallopian tubes via cilia found in the fimbria.

Hormone levels, specifically estrogen and testosterone, are peaking during this time. This can result in higher confidence and libido, a natural process of our body to externally guide us towards finding a partner to reproduce.


4) Luteal Phase:

The luteal phase begins on the 15th and lasts until the end of the cycle. During this phase, the egg cell stays in the fallopian for the first 12-24 hours. It is during this time that the egg cell must be impregnated by a sperm cell or the egg disintegrates. By the end of the cycle the endometrium (the mucous membrane in the uterus that prepares the uterus for pregnancy)  is used up, causing the initiation of the new menstrual cycle.

The estrogen and testosterone that was prominent in the ovulatory phase starts to decline. This is when progesterone starts to peak.

In addition, the female body is naturally slightly less insulin sensitive when progesterone levels are higher in the luteal phase (after ovulation, in the last two weeks of the cycle). This means the body does not tolerate carbohydrate as well in these weeks. Women who are diabetic know this well. I’ve read many studies and heard from many women who increase their insulin injections in the second half of their cycle because their blood sugar levels are inordinately high.

Since insulin sensitivity is at its lowest in the final two weeks of the cycle, and carb intake is also at its lowest, exercise should be more anaerobic (this means hard and fast, really getting your heart pumping). It should be focused more on high-intensity interval training, with short bursts of high intensity work, either from brief sprint exercises or from weight lifting. This is an excellent way to sharpen insulin sensitivity while simultaneously burning fat, increasing muscle mass, and spending calories. It also helps the body stay healthy and as stress-free as possible during this time in which the body is gearing up to menstruate and the least capable of handling stress.

A Few Important Things to Note Regarding Our Cycles:

  • Estrogen and progesterone are elevated at different points in the menstrual cycle. Estrogen levels tend to be the most dominant in the first and second weeks of the cycle (especially the second week). Progesterone levels are at their highest in the third and fourth week of the cycle. This can affect on our energy levels.
  • Period symptoms including blood shed, cramp types and amount, and hormonal effects can vary person to person.
  • Birth control is regulating our periods, so if you have been on birth control since you started your period, you may have a different flow then if you were to get off birth control.

Factors that Can Change Your Menstrual Cycle:

  • Stress:
    We have covered this quite a bit on the PfW blog. But just to remind you- stress causes our bodies to choose which functions are most necessary and appropriate in the moment of stress or danger. More than not, if your body is going through a period of distress, you will not menstruate – as it does not see this period of time as a safe time to reproduce. If you are looking to reproduce, this can be one of the primary things to concentrate on that will assist in conceiving.
  • Sleep :
    Irregular sleeping patterns will cause disruptive hormone secretion which can cause a lapse or change with your menstrual cycle. It is seriously so important to give your body an appropriate amount of rest!
  • Medical Conditions like PCOS or HA:
    Both of these conditions can affect hormone levels in the body, in turn affecting our periods. For women with HA (Hypothalamic Amenorrhea), the woman’s body believes it is starving so the body shuts down hormone production. The body does this based on our instincts. Being pregnant while starving is considered life threatening by the body, so the body does not allow reproduction to be a choice. Women with PCOS have an excess of hormone production resulting in inflammation, weight gain, high insulin levels, and more. Read more on PCOS here, and HA here.
  • Diet :
    This can most definitely affect your cycle. When I was vegetarian for 4+ years, I did not have a single period. I attribute this to the lack of nutrients I was giving my body. If your body is feeling deprived or missing crucial nutrients, it will stop producing the hormones needed to menstruate.
  • Routine Changes:
    Our body is cyclatory. We see this in our circadian rhythm and our menstrual cycle. If you switch positions at a job, or you move to the night shift, this disruption in your normal schedule can cause your menstrual cycle to shift resulting in longer or shorter cycles, or even missed cycles. This is usually not permanent.

Further Reading:

I know this is a lot of information, but I hope it’s useful for you. I really do notice a difference in my aerobic vs. anaerobic activity throughout my different phases, as well as my carbohydrate tolerance and overall energy levels. There are so many factors surrounding our menstrual cycles, especially because women can be so incredibly different. I have included a few extra links to further reading on PCOS and HA below for your reference.

I am always very curious as to how other women adjust to their different phases, or if any of their physiological or emotional responses vary from what I have researched. Drop me a comment with your feedback!

Hypothalamic Amenorhhea further reading:

PCOS further reading:


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