The Truth Behind Cycle Syncing: How to Eat and Train for Menstrual Health
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Join Dr. Kevin Schultz on the Foundational Health Podcast as he dives into the science behind menstrual cycles and their impact on exercise and nutrition. In this enlightening episode, Dr. Schultz addresses common misconceptions about cycle syncing and provides evidence-based insights into how women can optimize their health during different phases of their menstrual cycle.
Whether you're curious about how hormones affect muscle growth or seeking actionable lifestyle tips, this episode offers valuable takeaways for women of all ages. Tune in to discover how to balance hormones, improve overall health, and empower yourself with knowledge that transcends health trends and questionable research. Perfect for women, young girls, and anyone interested in foundational health practices.
Navigating Nutrition and Exercise for Women’s Health
Is there evidence in the literature that women and young girls should exercise differently in relation to the different phases of their menstrual cycle?
Does the phase of a menstrual cycle affect muscle and strength gains? Should females be eating differently during the different phases of their cycle? If I’m on birth control and not having a cycle, does that change how I should be exercising and eating?
These are the questions women of all ages—especially young girls—are asking as they try to sift through the noise of social media, online programs, and outdated assumptions. In this episode of the Foundational Health Podcast, Dr. Kevin Schultz unpacks the science behind menstrual cycles and separates evidence from myth when it comes to syncing your lifestyle with your hormones.
Whether you’re a woman currently menstruating or a parent of a teen trying to navigate this new season of health, this article will give you real science and practical takeaways for nutrition, movement, and hormone balance.
Understanding the Menstrual Cycle (And Why It Matters)
A woman’s menstrual cycle is often described in medical literature as a tidy 28-day process. In reality, though, the average cycle can range from 21 to 35 days. The confusion begins when we treat this as a one-size-fits-all model—especially in fitness and wellness culture.
The cycle is typically divided into four phases:
Menstrual Phase (Day 1–5): Low estrogen and progesterone, with bleeding.
Follicular Phase (Day 6–14): Estrogen rises, promoting follicle growth.
Ovulatory Phase (Day 14–16): Estrogen peaks; luteinizing hormone spikes.
Luteal Phase (Day 15–28): Progesterone rises; estrogen has a second, smaller peak.
Knowing what’s happening hormonally during these phases has sparked a rise in “cycle syncing” strategies—where women adjust their workouts and diets based on hormonal fluctuations. But is this actually backed by good research?
The Problem with Cycle Syncing: Rat Studies ≠ Human Truth
Many cycle syncing programs are rooted in the idea that progesterone is catabolic (breaks down muscle), while estrogen is anabolic (builds muscle). So, the theory goes: avoid strength training during the luteal phase and focus on building during the follicular phase.
But here’s the catch: this theory is mostly based on rodent research—not human studies. For example, many protocols emerged after scientists removed ovaries from mice to shut down progesterone production, then extrapolated the results to women.
Thankfully, researchers like Lauren Colenso-Semple are correcting the narrative. Her team has shown in human studies that muscle protein synthesis, recovery, and strength gains are not significantly impacted by menstrual cycle phase.
This is huge. It means that women don’t need to radically change their training schedule based solely on where they are in their cycle—unless their individual symptoms suggest otherwise.
“The body doesn’t work in isolation. It’s not just about progesterone or estrogen—it’s about how all hormones and systems interact in real time.” – Dr. Kevin Schultz
What About Birth Control?
If you’re on hormonal birth control and not experiencing a true menstrual cycle, the question becomes: should I still follow cycle syncing?
According to Dr. Schultz, no human studies show a significant difference in strength or muscle gain due to birth control use. While he strongly encourages women to research the long-term risks of hormonal contraception—including higher risks of stroke, cancer, and blood clots—the good news is that exercise and nutrition principles still apply.
Actionable Lifestyle Tips for Hormone Balance
Let’s get practical. Whether you’re cycling naturally, on birth control, or experiencing perimenopause, here are evidence-based tips for thriving through all phases:
Exercise Recommendations
Strength train 3x/week using weights, bands, or machines.
Hypertrophy rep range (10–12 reps to failure) is ideal for teens to 30s.
Women in late 30s–50s may benefit from “2 reps in reserve” training style.
Do HIIT 2–3x/week. Short bursts (20–60 seconds) with recovery improve growth hormone, metabolic function, and hormone regulation far better than long, slow cardio.
Note: Long-duration Zone 2 cardio may negatively impact female hormones and slow metabolism
Nutrition Tips
Eat within 30 minutes of waking to prevent cortisol crashes.
Fuel pre- and post-workout:
Pre: ~15–20g protein + ~30g carbs
Post: ~30–40g protein within 2 hours
Avoid fasted training as it may deplete muscle and bone mass over time.
Eat 3–4 protein-rich meals daily, aiming for 0.75–1.25g of protein per pound of ideal body weight.
Foundational Lifestyle
Track your cycle (don’t rely on generic app estimates).
Focus on organic whole foods—pesticides act as xenoestrogens that mimic estrogen and disrupt hormone balance.
Supplement with the Foundational Four:
Hydrate well, aiming for half your body weight in ounces of water per day.
Sleep deeply by reducing blue light, limiting caffeine, and winding down before bed.
Get daily sunlight, fresh air, and grounding time to support your circadian rhythm and hormone function.
Final Thoughts: What the Science Really Says
To answer the original question: Should women change their training and nutrition based on menstrual cycle phase?
According to current human research—including the work of Lauren Colenso-Semple and Dr. Stacy Sims—the answer is: only if your body is telling you to.
Don’t follow a cycle-syncing plan rooted in rodent models or synthetic hormone studies. Instead, track your symptoms, follow a foundational approach, and build your plan around how you actually feel, not what a social media coach tells you.
If you’re a mom, coach, or healthcare provider—please share this with the girls and women in your life. They deserve to start with truth, not trends.
Frequently Asked Questions About Women’s Menstrual Health
1. Should I change my workouts based on my menstrual cycle?
Not necessarily. According to human studies, including the work of researcher Lauren Colenso-Semple, the phase of your cycle does not significantly impact your ability to gain strength, build muscle, or maintain fitness. You can still train effectively throughout all phases, unless symptoms suggest otherwise.
2. Is it true that progesterone breaks down muscle, so I shouldn’t strength train during the luteal phase?
This theory comes primarily from mouse and rat studies, not human data. While progesterone has catabolic properties in isolation, your body doesn’t function in isolation. Real-world research in humans shows that women can build muscle and strength regardless of progesterone levels.
3. Can I build muscle while on hormonal birth control?
Yes. There is no strong evidence suggesting hormonal contraceptives impair muscle growth or strength. However, birth control does come with other risks (e.g., blood clots, cancer, mood changes), so it’s essential to evaluate long-term use from a whole-health perspective.
4. Does long cardio help or hurt female hormones?
Long-duration, steady-state cardio (like jogging for 45–60 minutes) may negatively affect female hormone balance, especially for women in their 30s–50s. Instead, short bursts of high-intensity interval training (HIIT) have been shown to better support hormonal health, muscle retention, and metabolic function.
5. What are the best nutrition habits to support hormone balance?
Eat within 30 minutes of waking to stabilize cortisol.
Avoid fasted training—especially long-term.
Prioritize high-quality protein (0.75–1.25g/lb ideal body weight).
Include pre- and post-workout nutrition.
Choose organic foods to reduce xenoestrogen exposure from pesticides.
