Debunked: Does your menstrual cycle really impact how you exercise?

It is hard to imagine a world where only men can sweat. 

This was the reality for much of the 20th century when women who exercised were considered unladylike. After World War II, when women started to enter the workforce and television became a common household device, one of the first exercise instructors on television, Bonnie Prudden, realized the importance of exercise for children, regardless of gender. In order to ease the tension of one mother who was worried that her daughter would become too muscular from exercise, Prudden said, “Under every curve is a muscle, no muscle, no curve, no curve, no husband.” This was in the 1950s, less than a century ago. Rather than focusing on the health benefits of exercise, women were more concerned with how it would make them desirable to men. Luckily, times have changed, but how can we get more women to work out in a way that is specific to them? 

For many, a weekly exercise regime is the standard, repeating the same exercises at the same weight. This has worked for men over history, but is it the most efficient way for women to work out? As women’s health becomes more recognized, the importance of a biological woman’s menstrual cycle has become a popular topic.

Before understanding the relationship between women’s exercise and their menstrual cycles, it is essential to explore the underlying biological factors. There are three phases to the menstrual cycle: the follicular, ovulation and the luteal phases. The length of each of these cycles varies, but the typical cycle lasts anywhere from 21 to 35 days. There are four significant hormones: luteinizing hormone, follicle-stimulating hormone, estrogen and progesterone. 

This is a short summary of what happens in each phase. 

• Follicular phase: This is when menstruation happens. Progesterone and estrogen levels drop, causing the top layer of the uterine lining to shed and cause bleeding. The hormone that stimulates follicles increases, causing them to form on the ovaries. Each follicle contains an egg that has yet to be released. Once these follicles form, follicle-stimulating hormone decreases and estrogen increases. This phase occurs from day 6 to 14. 
• Ovulation: Luteinizing and follicle-stimulating hormones rise rapidly, and the luteinizing hormone stimulates the release of the egg from the follicles. Estrogen levels start to decrease and progesterone begins to increase. This phase occurs typically on day 15.  
• Luteal phase: Luteinizing and follicle-stimulating hormone decrease, and the follicle closes after releasing its egg. This forms a corpus luteum, which produces progesterone. Estrogen levels remain high, causing the endometrium to thicken in preparation for fertilization. If the egg is not fertilized, progesterone is no longer produced as the corpus luteum will deteriorate, and estrogen levels also decrease, causing the endometrium to shed its top layer and repeat the cycle. This phase occurs from day 15 to 28. 

Now that we have a clearer understanding of the different phases of the menstrual cycle, let’s examine how these phases might intersect with women’s exercise routines. A meta-analysis about the effects of menstrual cycle phase on exercise performance included 78 past studies and found that women may have the weakest performance in physical activity during the early follicular period. This study has many limitations, and the conclusion is only trivial. The reason is primarily because there was a large amount of variance between the studies. 

Another study called “Effects of follicular versus luteal phase-based strength training in young women” observed 20 women with regular menstrual cycles during the late follicular and late luteal phases. The results found that muscle strength was higher following the follicular phase, which could be due to high rates of protein synthesis and breakdown after strength training. Hormonal differences between the two phases could be the cause, with more testosterone available during the follicular phase. During the late follicular phase, estrogen levels increase and progesterone is still low. Estrogen is known to suppress the breakdown of protein, which may allow more protein to be available when estrogen is high during the late follicular phase. Progesterone actually promotes the breakdown of protein, so this process would be minimized at the end of the follicular phase. Estrogen also has an influence on metabolism, helping glucose be more readily available for use by muscle fibers for energy during short-term workouts. Progesterone has opposing effects.

One element that these studies leave out is psychology. The menstrual cycle is known to be linked to different emotions. For example, a lot of eumenorrheic individuals experience moodiness and heightened emotions at the end of the luteal phase, which is also commonly known as PMS. A study about the Effect of menstrual cycle and exercise intensity on Psychological and physiological responses points out that having a regular workout routine is correlated with having positive feelings about exercise. This study followed 14 healthy eumenorrheic women as they completed exercise at both high and low intensities, dependent on their anaerobic thresholds during the follicular and luteal phases. In this study, they were able to find worse psychological responses before and after exercise during the luteal phase. This study did not find a difference between physiological responses between the luteal and follicular phases, which is interesting when compared to the previous study mentioned. Worse psychological responses could indicate lower motivation and higher amounts of stress and anxiety, which could deter women from exercising. 

Despite both studies having differing conclusions, what we do know is there is no one-size-fits-all workout routine for women. With the knowledge provided by continued research, we can make decisions that align with our physiological and psychological needs so that exercise fits our goals and lifestyle. If you are experiencing negative emotions during your luteal phase, maybe you can have some sort of higher reward after a workout or choose a less strenuous activity. Another idea would be to supplement your diet with more protein while progesterone levels are higher to reverse the extra protein that is being broken down. Essentially, your workout routine does not have to mirror what the influencer you see online does; it should be tailored to your body and your feelings. Of course, cycle tracking is one of the best ways to figure out which phase you are currently in. 

As we move forward, we have to recognize the huge steps we have taken in recognizing the intricate aspects of women’s health. The next time you work out, it is important to remember that you are doing something to empower yourself and build your health in a way that was robbed from the women who came before us.