Cycle Syncing: What The Evidence Really Says
You have probably seen the trend online. Colorful charts telling women exactly which workouts to do based on their menstrual cycle. Yoga during your period, heavy strength training around ovulation, steady-state cardio in the luteal phase.
It is catchy, marketable, and has become a buzzword in the wellness space. Influencers talk about it as if it is a revolutionary way to train “with your hormones” rather than against them.
But is this really the missing key to unlocking women’s fitness? Or is it another oversimplified trend?
Let’s take a closer look.
What is Cycle Syncing?
Cycle syncing is the idea that women should adjust nutrition, exercise, and even productivity based on the four phases of the menstrual cycle. The claim is that by matching workouts to hormone fluctuations, you can optimize energy, strength, and recovery.
It first gained attention through the book WomanCode by Alisa Vitti, who popularized the term and created programs around it. Since then, it has taken off on social media because it feels like a fresh, female-centered approach to health.
But while the concept is empowering on the surface, the scientific evidence behind it is not as solid as influencers make it sound.
A Quick Refresher: The Four Phases of the Menstrual Cycle
To understand where cycle syncing comes from, it helps to know what is happening hormonally during each phase of the cycle.
Menstrual Phase (Day 1 to ~5)
Bleeding begins. Estrogen and progesterone are at their lowest.
Common symptoms: cramps, low energy, fatigue.
Follicular Phase (~Day 1 to 14, overlaps with menstruation)
Estrogen begins to rise as the body prepares an egg.
Energy often improves after menstruation ends. Some women feel stronger and more motivated.
Ovulation (~Day 14 in a 28-day cycle, but highly variable)
Estrogen peaks. Luteinizing hormone surges to release an egg.
Some report higher energy, strength, and even faster recovery.
Luteal Phase (~Day 15 to 28)
Progesterone rises to prepare for a potential pregnancy. Estrogen drops after ovulation but rises again mid-luteal before falling.
Symptoms can include bloating, mood changes, PMS, and fatigue as the cycle nears menstruation again.
Here’s a graphic showing the four phases of the menstrual cycle with approximate hormone changes:
Estrogen (purple): Rises during the follicular phase and peaks just before ovulation.
Progesterone (orange): Rises after ovulation and dominates the luteal phase.
LH (green, dashed): Sharp surge triggers ovulation.
FSH (blue, dashed): Small rises early in the cycle and again mid-cycle.
Shaded regions show the menstrual, follicular, ovulation, and luteal phases.
Cycle syncing programs often recommend training with these shifts. For example, low intensity during menstruation, heavy lifting around ovulation, and lower-impact exercise during the luteal phase.
What the Science Actually Says
While this framework sounds logical, the evidence is inconsistent. Here is what research shows:
Network Meta-Analysis (McNulty et al., 2020): Looked at exercise performance across menstrual phases. Found performance may be slightly reduced in the early follicular phase, but the effect was small and highly variable. The overall evidence quality was rated as low.
Umbrella Review (Sung et al., 2023): Analyzed multiple systematic reviews on menstrual cycle and resistance training. Concluded there is little to no meaningful effect of menstrual cycle phase on acute strength, endurance, or training adaptations.
Individual Variability: Studies consistently show that women respond differently. One woman may feel strong during ovulation, while another feels no difference at all. Some experience severe PMS, others barely notice symptoms. This variability makes it nearly impossible to prescribe universal “phase-based” training rules.
In other words, while hormones do fluctuate across the cycle, translating that into a hard rule like “do HIIT on day 14” is not supported by robust data.
Why Cycle Syncing Took Off Anyway
If the evidence is weak, why is cycle syncing everywhere?
It is easy to explain. A neat four-phase chart is simpler than teaching autoregulation or training science.
It sells. Programs, courses, and apps can market it as a unique solution “just for women.”
It feels empowering. After years of fitness advice centered on men, the idea of syncing with your hormones resonates.
There is nothing wrong with noticing personal patterns. If you feel better doing lighter workouts during your period, that is valid. The problem is when cycle syncing is presented as a science-backed rule for all women.
The Better Alternative: Autoregulation
Rather than forcing your body into a calendar template, autoregulation allows you to adjust training based on your readiness each day.
Autoregulation uses tools like:
RPE (Rate of Perceived Exertion): Adjust loads based on how hard a set feels.
RIR (Reps in Reserve): Stop sets with a few reps left in the tank, adjusting for the day.
Ranges instead of absolutes: Write “3 to 5 sets” instead of a strict “4 sets.”
Traffic light method: Green days, push. Yellow days, scale back. Red days, swap for something gentler.
This method accounts for hormone shifts and everything else that impacts performance like stress, sleep, and nutrition. It is not about ignoring your cycle, but about listening to your body more closely and responding in real time.
The Bottom Line
Cycle syncing is trendy, marketable, and resonates with women who want fitness advice tailored to them. But the science does not support it as a universal training method. Hormones do fluctuate, but the effects on performance are too inconsistent and too individual to justify rigid programming.
Autoregulation, on the other hand, is supported by research and puts the control back in your hands. It teaches you to listen to your body, respect your limits, and maximize your strong days without guilt on the tough ones.
So instead of asking, “What workout does my app say I should do today?” start asking, “What is my body ready for today?”
Want Help Learning Autoregulation?
This is exactly where coaching comes in. I help women build customized training programs that adapt to their bodies, cycles, and lives. With guidance, you can:
Learn how to adjust your workouts without losing progress.
Understand when to push harder and when to pull back.
Stay consistent year-round, even through the ups and downs of your cycle.
👉 Click here to learn more about my coaching and let’s build a plan that works for you, every day of the month.
Coach Krys