New Study Disproves Myth About Women's Muscle Growth and Menstrual Cycle Timing

A recent study conducted by kinesiologists at McMaster University has challenged the widely held belief that women can enhance muscle growth and strength by timing their resistance training around their menstrual cycles. The research findings indicate that the timing of workouts has no significant effect on muscle protein synthesis, a crucial process for building and maintaining muscle mass.

The study, published in the Journal of Physiology, contradicts the popular practice known as cycle syncing, which involves adjusting exercise routines to align with hormonal fluctuations throughout the menstrual cycle. According to the lead researcher, there were no observable differences in muscle protein synthesis regardless of the phase of the menstrual cycle in which the exercises were performed.

To carry out the study, researchers monitored the menstrual cycles of healthy young female participants over a span of three months to ensure that their cycles were regular. The findings revealed that only about 12% of women have a consistent 28-day cycle with ovulation occurring on day 14, which is often referred to as the 'textbook' cycle.

Each participant ingested a tracer molecule, a harmless substance used to track muscle protein levels, and engaged in heavy resistance training during two distinct phases of their menstrual cycles: the follicular phase, characterized by peak estrogen levels, and the luteal phase, which is marked by higher progesterone levels. The results showed no effect of the menstrual cycle phase on muscle protein production.

Cycle syncing has been popularized by social media influencers, who advocate for tailoring workouts, diets, and lifestyle choices to the different phases of the menstrual cycle. These proponents often reference limited studies conducted on animals as evidence of hormonal effects on muscle responses in humans, but the McMaster study challenges this notion.

The supervising researcher emphasized that women who intend to engage in weight lifting or muscle conditioning can do so at any phase of their menstrual cycle without concern for physiological differences in their responses to exercise. The focus should instead be on how one feels and their personal preferences when it comes to training.

Experts in the field have called for additional research, particularly studies that explore women's health in relation to exercise and the menstrual cycle. There is a recognized need to examine how both oral and non-oral contraceptives may influence women's responses to physical activity.

This study not only sheds light on the misconceptions surrounding women's exercise regimens but also encourages women to prioritize their personal training preferences and well-being over societal myths.