At 41, a doctor told Penélope Cruz that in the coming years her hormones would swing up and down with no particular logic. "I thought that was a really bad joke," the actress says now, at 52. More than a decade later she still has a monthly cycle - and still lives those swings. "The ups and downs can be pretty crazy."

The story is not about Cruz. The story is about how long women have been handed the wrong timeline. For decades menopause was explained as a switch: at 50 the cycle stops, the hot flushes start, the end. The body does not work like that. Before the last cycle there is a transitional period of several years in which hormones shift while body and mind are already reacting. It is called perimenopause, and the biggest problem with it is that many women do not know it exists as a distinct phase.

The World Health Organization defines it as the period beginning with the first signs of change in the menstrual cycle and lasting until one year after the final period. It can go on for several years. Menopause itself is a precisely defined moment - twelve consecutive months without a cycle, provided the absence has no other explanation. The WHO places natural menopause between 45 and 55; in Spain the average is around 49.

Why nobody recognises it in time

Because the symptoms arrive gradually and each one has a more comfortable explanation. The cycle comes early or late, gets heavier or more frequent. There are night wakings, constant fatigue, irritability, brain fog, palpitations, muscle discomfort, vaginal dryness, hot flushes, night sweats. All of it looks like stress, poor sleep, too much work.

"One of the main problems with perimenopause is that the symptoms usually appear gradually and get attributed to other causes. Many women come in because of insomnia, irritability or fatigue without connecting it to a hormonal origin. Recognising this phase allows earlier action and improvement," explains Ana María Román, head of gynaecology at a private clinic in Madrid.

There is an emotional side too. Hormonal swings affect the neurotransmitters linked to mood and can increase sensitivity to stress or trigger episodes of anxiety. And that usually coincides with a stage of life that carries plenty even without hormones - children, parents, career, bills.

What helps, and what is not compulsory

Not every woman needs therapy. But it does not follow that suffering is to be taken for granted. If the symptoms are wrecking sleep, work, emotional state or sex life, that is reason enough to see a doctor and look at the options, including hormone therapy where it is indicated.

The everyday measures are not marketing: recording the changes in your cycle - whether it comes early, whether it drags on, whether the intensity changes - is data worth having at an appointment. Then sleep, regular physical activity and a diet with enough protein, calcium and vitamin D. Exercise here is not aesthetics; it is bone and function.

And one line that must not be crossed: if the bleeding becomes very heavy, lasts longer than usual, appears between cycles or returns after a long absence - that does not get written off as perimenopause. That gets checked.

Cruz told her story from a position where few people believe she has a problem. That is exactly why it matters. The message is not that everyone will go through the same thing - experiences differ drastically. The message is that the body starts changing while the cycle is still running, and that waiting for periods to disappear before understanding what is happening means losing years in which someone could have helped.