As climbers, we experience a unique physiological journey each month: the menstrual cycle. Although it has historically been under-researched and often considered taboo in sports, its influence on performance, strength, and recovery is undeniable. In recent years, science has begun to reveal how hormonal fluctuations can be a powerful tool to optimize our training and minimize injury risk.

In this post, we’ll explore why this topic has been ignored, what happens in each phase of the cycle, and—most importantly—how we can adapt our training plans to climb more and better, in tune with our bodies.

The Silent Past: Why Has Research Left Us Behind?

For a long time, the relationship between menstruation and sports performance has been little explored. Several reasons have contributed to this scientific silence:

Gender Bias in Research: Historically, studies have focused on men, wrongly assuming that results were directly applicable to women. Female hormonal variability was seen as a “complication” for analysis, leading to lower representation of women in research.
Methodological Difficulties: The menstrual cycle introduces significant physiological variability, with fluctuations in estrogen and progesterone affecting physical performance, motivation, mood, and perceived effort. This requires rigorous experimental designs and constant monitoring, increasing the complexity and cost of studies.
Individual Variability: Every woman is different. Responses to the cycle vary greatly, both in symptoms and phase duration, making it difficult to identify clear, generalizable patterns.
Lack of Knowledge and Awareness: Menstruation has been a taboo topic, perpetuating a lack of understanding about its impact on sports performance. Only with greater female participation in elite sports has the need arisen to understand and optimize training according to the cycle.

Fortunately, this situation is changing, and a recent systematic review (Niering, 2024) is shedding light on the influence of the menstrual cycle on strength training.

Your Biological Clock: Phases of the Menstrual Cycle and Their Hormones

An average menstrual cycle lasts 28 days, but can vary between 21 and 35 days in healthy women. During this time, estrogen and progesterone concentrations fluctuate, significantly influencing your body.

The key phases and their hormonal profiles are:

Early Follicular Phase (Days 1-5 approx.): Low levels of estrogen and progesterone (coincides with menstruation).
Late Follicular Phase (Days 6-13 approx.): Rising estrogen levels.
Ovulatory Phase (Day 14-15 approx.): High estrogen and a gradual increase in progesterone. There is also usually a testosterone peak.
Early Luteal Phase (Days 15-20 approx.): Predominant increase in progesterone.
Mid Luteal Phase (Days 20-24 approx.): Peak levels of estrogen and progesterone.
Late Luteal Phase (Days 25-28 approx.): Decrease in both hormone levels, signaling the start of menstruation.

Hormonal Impact: Hormones, Metabolism, and Body Composition

Female sex hormones, energy metabolism, and body composition are the main factors influencing strength expression and performance.

Sex Hormones:
- Estrogen enhances nerve and muscle function, improving strength and performance. It increases muscle protein synthesis and the number of active myosin heads, essential for muscle contraction. High estrogen levels (late follicular phase) are associated with better maximal strength performance.
- Progesterone has the opposite effect, inhibiting cortical excitability in the brain and partially counteracting estrogen’s anabolic effect in the mid-luteal phase.
- Testosterone also contributes to physical performance, peaking during the ovulatory phase.
- Additionally, estrogen affects the enzyme lysyl oxidase, key for collagen production, which may mean less tendon stiffness in women and a greater tendency for ligament injuries.
Energy Metabolism:
- In the mid-luteal phase, the body prioritizes fat metabolism and decreases carbohydrate use, which may favor endurance performance.
- The late follicular phase is favorable for glucose utilization due to increased insulin sensitivity, benefiting intensive, short-duration exercise.
Body Composition: An increase in body mass and total body water has been observed from the follicular to the luteal phase, which could negatively affect aerobic and anaerobic endurance performance, and indirectly, maximal strength.

Strength in Each Phase: When Are You Strongest?

Although study quality still presents methodological limitations, trends suggest:

Maximal Isometric Strength: Enhanced during the late follicular phase, followed by the ovulatory phase, and decreased in the luteal phase and menstruation. This aligns with estrogen peaks and low progesterone.
Maximal Dynamic Strength: Evidence is weaker, but the late follicular phase may be most suitable. High estrogen in this phase promotes protein synthesis, hypertrophy, and recovery.
Explosive Strength (Jumps and Plyometrics): Paradoxically, explosive performance may decrease in the late follicular phase, possibly due to reduced muscle-tendon stiffness or increased joint laxity, associated with high estrogen and low progesterone.

Climbing and Your Cycle: Practical Recommendations

Currently, there are no specific studies on the influence of the menstrual cycle in climbers. However, we can extrapolate conclusions (though still weak) from other sports to guide our training. It’s crucial to remember that each athlete responds differently to hormonal variations.

Here’s a phase-based guide, always prioritizing individuality and listening to your body:

Menstruation (Early Follicular Phase):
- Hormonal Profile: Estrogen and progesterone at their lowest.
- Recommendation: Many athletes experience a loss of performance. A cycle with low loads or even rest is suggested. However, if you feel good, you can maintain intense training.
Follicular Phase:
- Hormonal Profile: Rising estrogens, low progesterone.
- Recommendation: Your body is ready! Strength is enhanced and recovery improves. It’s an ideal time for high-intensity strength training (up to 3-4 days/week), with longer sessions and higher frequency.
Ovulatory Phase:
- Hormonal Profile: Sharp drop in estrogens and rise in progesterone.
- Recommendation: A decrease in recovery capacity, strength, and endurance has been observed. After the intensity of the follicular phase, a deload or rest cycle is advised.
Luteal Phase:
- Hormonal Profile: Estrogens rise again, but progesterone increases more, counteracting some of its effects. There’s a predominance of oxidative metabolism.
- Recommendation: Good time for developing physical qualities with medium intensities and slightly higher volumes. It may be ideal for slow oxidative endurance training.
- Injury Warning!: The hormone relaxin increases in this phase (days 12-24 in 28-day cycles), decreasing collagen synthesis and tendon stiffness, which can increase the risk of ligament injuries (especially in the anterior cruciate ligament of the knee). It’s recommended to avoid highly demanding movements for ligaments (like high heels or aggressive mantles) and excessive flexibility training.

Conclusion: Your Body, Your Guide

Training planning, especially in the context of the menstrual cycle, is a powerful tool for climbers. Although research is still developing and we need more sport-specific studies, understanding hormonal trends and their effects on your body allows you to make more informed decisions, optimize your performance peaks, and protect yourself from possible injuries.

Listen to your body, track your cycle, and work with your coach to design a strategy that celebrates your unique physiology. This way, you can keep pushing your limits on the wall, in harmony with your cycle!