Hello, underwater explorers!
What you’re about to read is the result of research conducted while writing The Depth Collector: Book Two.
So, grab your nose clip, take a deep breath, and get ready to explore a fascinating and often overlooked topic—Freediving and the Menstrual Cycle: The World of the Female Freediver.
Jiayin (my amazing wife, Molchanovs Instructor Trainer, and co-founder of VD Freediving Taiwan) loves DNF. She spends hours in the pool, refining her movements and striving for perfection. Over time, we noticed a clear pattern—some days, she was full of energy and focus, while on others, she felt more fatigued, less sharp, and had an increased urge to breathe earlier than usual.
Curious about these fluctuations, we started digging into how hormonal changes impact female freedivers—and surprisingly, there wasn’t much information readily available on the topic. The menstrual cycle remains one of the most overlooked aspects of female athletic performance. Unfortunately, most available data is based on male physiology, leaving a significant gap in understanding how training should be adapted for female athletes. In freediving, where internal chemistry (like CO₂ tolerance) plays a crucial role, these hormonal shifts can have a profound impact.
To gain a better understanding and help Jiayin fine-tune her training, I gathered insights from Jiayin herself, Angela Leibinger (founder of Breathing Spell Coaching), and other female freedivers and athletes who shared their experiences. I’ve done my best to summarize what I’ve learned, but I know I’m only scratching the surface. There’s still so much to explore, and I’m eager to keep learning. I hope this sparks discussions, encourages knowledge-sharing, and leads to a more informed approach to training for female freedivers.
Understanding the Menstrual Cycle’s Impact on Training
I knew almost nothing about this topic before, so this explanation is for people like me—those who have no clue how female biology actually works but want to learn.
The menstrual cycle typically lasts between 24 and 36 days, with an average of 28 days, though only about 10-15% of women have a cycle that perfectly aligns with that number. It’s divided into four distinct phases, each affecting energy levels, muscle recovery, and CO₂ tolerance in different ways:
1. Menstruation (Day 1-4 to 8)
Hormonal Influence: Progesterone drops, while estrogen remains low.
Energy Levels: Often lower, with increased risk of injury and discomfort.
Training Considerations: Light activity is recommended. Some women feel great during static breath-holds, but intense workouts should be approached with caution.
2. Follicular Phase (Day 5-13)
Hormonal Influence: Estrogen rises, while progesterone remains low.
Energy Levels: Increasing energy, improved muscle-building capacity, and enhanced metabolism.
Training Considerations: This is a great time for high-intensity training and PB attempts. Muscle recovery is efficient, and CO₂ tolerance is at its peak.
3. Ovulation (Day 14)
Hormonal Influence: Estrogen peaks, then drops.
Energy Levels: High, but ligament elasticity increases, making injuries more likely.
Training Considerations: Ideal for PB attempts and deep dives. However, be mindful of joint stability.
4. Luteal Phase (Day 15-28)
Hormonal Influence: Progesterone rises, peaking before menstruation, then declines.
Energy Levels: Fluctuate, often decreasing toward the end of the phase.
Training Considerations: As progesterone rises, CO₂ tolerance decreases, leading to a greater tendency to hyperventilate. This is a good time to focus on technique rather than pushing limits.
Practical Applications for Freedivers
1. Aligning Training with the Cycle
It seems that tailoring freediving training to the menstrual cycle can enhance both performance and recovery. Rather than fighting against hormonal changes, female athletes can work with their bodies to maximize training efficiency and prevent overtraining.
PB attempts and intense workouts: Best during the follicular phase and ovulation.
Technique work, endurance, and CO₂ tolerance training: Ideal for the luteal phase.
Deloading and recovery: Should be prioritized during menstruation.
2. Adjusting for CO₂ Tolerance
One of the most significant impacts of the menstrual cycle on freediving is the fluctuation in CO₂ tolerance. During the luteal phase, when CO₂ tolerance is lower, focusing on relaxation techniques and CO₂ training can help mitigate the impact. Yes, the urge to breathe comes earlier, but it makes CO₂ training shorter while still highly effective.
3. Nutrition and Lifestyle Considerations
I’ve always been fascinated by nutrition. Jiayin… not so much. Taiwanese culture is arguably even more obsessed with food than French culture (oui oui, I admit it), and she’s definitely “gourmande.” But to her credit, she’s made a real effort and has implemented a few simple rules:
She takes iron supplements: Women need nearly twice the amount of iron as men, especially during menstruation.
She stays on top of hydration: Drinking plenty of water and adding electrolytes helps keep her energy levels steady.
She tries her best to avoid processed foods, sugar, and excessive caffeine: It’s great for hormonal balance… but let’s be honest, sometimes we take a little cake break. No need to hit a PB to earn a treat, right?
Final Thoughts
Freediving is all about adapting—whether to depth, pressure, or the incredible chemistry shift happening in our cells. Tracking the menstrual cycle and adjusting training accordingly isn’t just about improving performance; it’s about working with the body rather than against it. Since implementing this approach in Jiayin’s training, we’ve seen real benefits, and I know there’s still so much more to learn.
The truth is, we need more discussions, more research, and more people interested in this topic. Too much of sports science is still centered around male physiology, leaving women to figure things out on their own. That shouldn’t be the case. Hormonal fluctuations aren’t a limitation—they can actually be a strength when training is adapted accordingly. The more we open up this conversation, the more we can learn, grow, and evolve. Freediving is all about pushing limits, and that includes breaking down outdated training models. Let’s keep the discussion going, challenge old norms, and create a future where female freedivers have the knowledge they deserve to train smarter, perform better, and feel stronger in the water.
To be continued…
If what you’ve just read sparked your curiosity, know this—it’s just a ripple on the surface. The Depth Collector series plunges deep into this pillar, uncovering layers of insights, lessons, and practical tools to refine your freediving journey.
And it doesn’t stop here. The series explores all eight foundational pillars, packed with everything from mental hacks to sport nutrition, breathing techniques, training plans, and more.
Read more about the other pillars on the blog or grab your copy here.
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