
December 12, 2025 Coach MaxPhysiology
Optimizing Endurance Training for Female Physiology
Women are Not Small Men
For decades, sports science was based on 70kg college-aged males. We now know that female physiology requires a unique approach, specifically surrounding the menstrual cycle.
The Cycle Phases
1. Low Hormone Phase (Follicular)
- When: Day 1 (Period start) to Day 14 (Ovulation).
- Physiology: Estrogen and Progesterone are low. Similar to male physiology.
- Training: This is your time to SMASH IT. High intensity, VO2 max, and heavy lifting. Your body recovers faster and builds muscle easier here.
2. High Hormone Phase (Luteal)
- When: Day 15 (Ovulation) to Day 28.
- Physiology: Progesterone rises (increasing body temp and resting HR) and Estrogen fluctuates. Plasma volume decreases.
- Training: Everything feels harder. It's harder to hit top-end power. Focus on steady-state endurance (Zone 2) and technique. Be kind to yourself in the days before your period (PMS).
Nutrition Needs
Women oxidize fat differently and rely more on blood glucose during the high-hormone phase.
- Carbs: You need MORE carbs during the luteal phase, not less. Cutting carbs here can trigger a stress response (cortisol).
- Protein: Essential post-workout to signal muscle repair, especially as progesterone is catabolic (breaks down muscle).
The Danger Zone: RED-S
Relative Energy Deficiency in Sport. If you underheat, your body shuts down "non-essential" functions—like reproduction.
- Sign: Loss of period (Amenorrhea). THIS IS NOT NORMAL OR "PRO". It is a sign of a body in crisis.
- Risk: Low bone density (stress fractures) and hormonal crash.
Summary
Track your cycle like you track your FTP. It is a vital vital sign. Work with your physiology, not against it.