What are the four phases of the menstrual cycle?
A menstrual cycle runs from the first day of one period to the first day of the next, and it has four phases: the menstrual phase, the follicular phase, ovulation, and the luteal phase. Each is defined by what estrogen and progesterone are doing, and those shifts have real effects on how you feel and perform. The textbook cycle is 28 days, but anything from roughly 21 to 35 days is normal, and almost no one is exactly average.
| Phase | Hormones | How many tend to feel | Training tendency |
|---|---|---|---|
| Menstrual (period) | Both low | Variable, often better than expected once flow starts | Train to feel, fuel iron-aware |
| Follicular | Estrogen rising | Strong, motivated, good recovery | Quality runs, heavier lifting |
| Ovulatory | Estrogen peaks | Often a high for hard efforts | Hard work, mind joint laxity |
| Luteal | Progesterone high, then both fall | Higher effort, warmer, rockier sleep, PMS late | Recovery-leaning, smarter fueling |
The menstrual phase
Your period. Both hormones are at their lowest. Many women feel low on the first day or two, then surprisingly good as estrogen begins to climb. The main training consideration is iron: bleeding plus hard work is where iron slips. See running on your period.
The follicular phase
From the end of your period to ovulation, estrogen rises toward its peak. For many women this is the strongest window: good mood, efficient recovery, and a given effort feels easier. It is the natural home for your hardest running and heaviest lifting. See follicular phase training.
The ovulatory phase
Estrogen peaks and an egg is released, around the middle of the cycle for a textbook 28-day cycle, though timing varies. Many women feel at their strongest here. Higher estrogen is linked with greater joint laxity for some, so warm up well and keep progression sensible.
The luteal phase
After ovulation, progesterone rises, raising your resting effort and body temperature and, for some, disrupting sleep, before both hormones fall and PMS arrives in the days before your period. It is the phase that most often feels harder, and the one where a generic plan goes wrong. See luteal phase workouts.
Why the textbook 28-day cycle fails you
Most cycle advice assumes a perfect 28-day cycle and a fixed ovulation day. Real cycles vary in length month to month, and they shorten, lengthen, and skip in perimenopause. Rigid phase-by-phase rules built on an average are wrong most months, which is exactly why the most useful approach leads with your real cycle and how you feel today, not a calendar. See cycle-based training.
How Phaes uses your phases
Phaes anchors to the cycle starts you log and projects your phases on demand, then reads a daily check-in, so it biases quality work toward the windows you build best and eases off when the same load would cost more, no chart-tracking required. See cycle syncing workouts and how to track your cycle.