Menstrual Cycle Based Exercise Recommendations
Changing workouts according to a woman’s menstrual cycle has been recently disproven by tons of research. But many influencers and pseudoscience practitioners still push the idea that women need to lift lighter certain weeks and heavier other weeks. The idea behind adjusting workouts according to the menstrual cycle is say women should lift heavier weights during the follicular phase (the first half of the menstrual cycle) and women should lift lighter during the luteal phase (the second half of the cycle).
When women have higher estrogen levels, it’s suggested they have more energy and strength. This makes it optimal to lift heavier weights. Conversely, when estrogen levels are declining and progesterone levels are rising, women experience decreased energy, endurance, and strength. This is why some coaches advise women to lift heavier during the follicular phase and lighter on the luteal phase.
It’s important to note that scientific evidence does not support this. Research has shown that menstrual cycle phases do not impact acute strength performance or adaptions to resistance or endurance training in women. The idea that women should change their workouts according to the phase of their menstrual cycle lacks scientific validity.
Recent research challenges the idea that menstrual cycle phases influence exercise performance and training adaptations in women. The paradigm shift comes from a deeper understanding of physiological factors like neuromuscular function, muscle protein synthesis, and hormonal fluctuations throughout the menstrual cycle. New scientific evidence shows these physiological factors work together to maintain a consistent physiological environment conducive to normal training across menstrual cycle phases.
Physiological Functions
Neuromuscular function determines exercise performance and includes factors like muscle recruitment, coordination, and force production. While hormonal fluctuations occur during the menstrual cycle, studies show that neuromuscular function remains relatively stable throughout the cycle. There’s no difference in motor unit recruitment, muscle activation patterns, or force production between phases. This showcases women maintain consistent neuromuscular capabilities regardless of hormonal variations.
Muscle protein synthesis, which signals muscle repair and growth, is unaffected by menstrual cycle phases as well. Estrogen and progesterone levels fluctuate throughout the cycle but research has found no difference in muscle protein synthesis is not correlated with estrogen and progesterone. This means women can effectively repair and adapt to exercise stimuli throughout all phases of the menstrual cycle.
The interactions between neuromuscular function, muscle protein synthesis, and hormonal fluctuations support the idea that women can achieve consistent responses to exercise across the different menstrual cycle phases.
Why Do Some People Believe This Myth?
Historically, women have been excluded in exercise science research. This has lead in consequence to a limited understanding of women’s unique physiological responses to exercise. Most research explores men which leads to a knowledge gap that has contributed to many myths about women’s exercise needs.
This list wouldn’t be complete without anecdotal evidence taking a big role. Some women subjectively believe their energy levels, strength, or mood throughout their cycles and attribute the changes to hormonal fluctuations. Individual variation in menstrual cycle symptoms and experiences is quite common. However this does not necessarily translate to significant differences in exercise performance or training adaptations.
Once a belief enters pop culture or fitness communities, individuals may selectively interpret information and look for evidence that confirms their existing beliefs. Confirmation bias leads people to overlook contradictory evidence that challenges the validity of the myth. Cultural norms and societal expectations surrounding women and women’s health can positively influence the idea that menstrual cycle-based exercise recommendations, regardless of scientific evidence.
Final Thoughts
Knowledge is power when it comes to dispelling myths surrounding women’s physiology. Understanding the physiological responses to fluctuating hormones disproves women’s need to alter their strength and/or endurance workouts. They don’t need to match their workouts different phases in a menstrual cycle. If fluctuating progesterone and estrogen would impact neuromuscular function or muscle protein synthesis, the myth might hold. However, hormonal fluctuations are not impacting neuromuscular function and muscle protein synthesis, making this concept another myth spread by the fitness industry.
