Understanding Your Menstrual Cycle

Most people with a menstrual cycle learn the basics at school and then not much more. The period arrives, they manage it, and the rest of the month goes by without much thought about what the cycle is actually doing. But the cycle is a continuous hormonal process with distinct phases, each of which affects energy, mood, cognition, appetite, libido, and physical performance in ways that are worth knowing about.

Understanding your cycle isn't about optimising or hacking it. It's about having useful information that helps you make sense of how you feel and why, rather than treating each shift as a random inconvenience.

Phase one: menstruation

The cycle begins, conventionally, with the first day of the period. Oestrogen and progesterone are at their lowest, the uterine lining sheds, and for many people this is the phase that involves the most physical discomfort. Energy tends to be lower, and many people find they feel more introspective or quieter than usual. This is a physiologically demanding phase and scaling back where possible, rather than pushing through, is a reasonable response to what the body is doing.

Period pain that is severe, that disrupts daily life, or that has worsened over time is worth discussing with a GP. It can indicate conditions such as endometriosis or adenomyosis that benefit from investigation and support.

Phase two: the follicular phase

As the period ends, oestrogen begins to rise as the ovaries prepare to release an egg. This phase tends to feel noticeably different: energy increases, mood often lifts, concentration sharpens, and many people find they feel more sociable and motivated. The rising oestrogen also supports serotonin production, which contributes to the lift in mood.

This phase typically runs from the end of the period to ovulation, roughly days five to thirteen in a 28-day cycle, though timings vary considerably between individuals.

"The cycle isn't just about the period. It's a monthly rhythm that influences how the body and mind operate throughout. Recognising that rhythm makes it considerably easier to work with."

Phase three: ovulation

Ovulation, the release of an egg from the ovary, is triggered by a surge in luteinising hormone and marks the midpoint of the cycle. Oestrogen peaks just before ovulation, and many people feel at their most energetic, confident, and outwardly focused during this window. Libido commonly increases. The fertile window spans the few days around ovulation.

Some people experience a brief, sharp pain on one side around ovulation, called mittelschmerz, along with a change in cervical mucus to a clearer, more stretchy consistency. These are normal physiological signs that ovulation is occurring.

Phase four: the luteal phase

After ovulation, the follicle that released the egg becomes the corpus luteum and begins producing progesterone. This is the phase that runs from ovulation to the start of the next period, typically around 12 to 14 days. Progesterone has a calming, slightly sedating effect; energy may dip, and many people find they feel less social and more inward-facing in the second half of this phase.

In the days before a period, both oestrogen and progesterone drop sharply. For many people this drop produces premenstrual symptoms including mood changes, irritability, fatigue, bloating, and breast tenderness. These are normal to experience in mild form, but significant premenstrual symptoms that affect daily functioning may indicate PMDD (premenstrual dysphoric disorder) or a hormonal imbalance worth exploring with a doctor or specialist.

Your cycle is one of the more informative things about your overall health. Paying attention to it, and knowing when something feels off, is a genuinely useful habit.