New Study Reveals Whether Muscle Gains Are Actually Linked To The Menstrual Cycle

Syncing your workouts to your menstrual cycle is a newish concept that's piqued the interest of women. 

For example, it's often encouraged to prioritize energy-intensive lifting and HIIT classes to align with your often more energized follicular phase and lower-intensive movement (like Pilates or yoga) during your more sluggish-feeling luteal phase.

And while you always have to meet your body where it's at for a workout, are there any physiological benefits to structuring your exercise routine around your cycle? 

Well, a newly published study is one of the first to investigate the impact of strength training and muscle protein synthesis and breakdown rates in menstruating women.

Estrogen and progesterone are two hormones that characterize the menstrual cycle and influence how you think and feel during that time. 

Based on these known hormonal fluctuations and the general impacts of these hormones, researchers of this study hypothesized that muscle protein synthesis would increase more during the follicular phase than luteal in response to strength training. 

A total of 12 women ages 18 to 30 with a regular menstrual cycle (and no current or recent use of hormonal contraceptives) completed the study. Even though 12 seems like a small number, it was a large enough group to showcase any significant findings since prior research in this area is so limited (thanks to the gender gap in research).

Each woman underwent two six-day study phases: one during their follicular phase and one during the luteal (these were confirmed via hormone blood tests). 

During both phases, researchers then used muscle biopsies to measure muscle protein synthesis and muscle protein breakdown following a lower-body strength training exercise. 

This study is truly foundational in helping us better understand the muscular responses to exercise during different phases of the cycle. 

So, although there is a fluctuation in hormones, it does not seem to impact your ability to build muscle. Avoiding higher-intensity workouts just because you're in your luteal phase means you're also missing out on the benefits of that exercise. 

However, these hormone fluctuations still impact how you feel—which can impact your workout. 

"Women feel very different during their cycle. The key is to listen to YOUR body and do what feels right," Ellen Vora, M.D., previously shared with mindbodygreen. 

Certified exercise physiologist Rachelle Reed, Ph.D., ACSM-EP, has previously emphasized that workouts should be "customized to the individual." 

So, maybe that doesn't mean always skipping a weight day during your luteal phase, but listening to your body and recognizing that you are not up for picking the heaviest weights that day. Or maybe you max out at six reps instead of eight. 

While a woman's cycle is characterized by changing hormone levels, those hormones don't seem to impact muscle growth or breakdown. Exercise at any point of the month is beneficial for building muscle, and you don't have to tailor your workouts exactly to your menstrual phase.