If the word perimenopause makes you brace a little, you are not alone. It gets talked about like something to survive, not something you can prepare for.

As a Physiotherapist, I want to talk about it differently. It is a transition you can prepare for, train for and move through with more control than you might expect. Understanding what is changing in your body is where that control starts.

Perimenopause is the years before your final period, when your ovaries gradually produce less oestrogen and progesterone. It typically begins in your mid-thirties to mid-forties, though the timing is different for every body. It lasts around four years on average, sometimes longer. Hormone levels do not decline in a straight line during this time, they rise and fall unpredictably, which is why symptoms can feel inconsistent from one month to the next.

Why your muscle needs protecting first

One of the biggest changes happens in your muscle mass. Oestrogen plays a direct role in how muscle is repaired and rebuilt, so as it declines through perimenopause, muscle loss speeds up. From your thirties onwards, muscle mass declines at a rate of roughly three to eight percent per decade, rising to five to ten percent per decade from your fifties. The decline accelerates through this transition, which is why strength training needs to become a core priority, not a supplement to other workouts.

The encouraging part is that this is one of the most preventable parts of the whole process. Strength training is the single most effective tool you have to protect the muscle you carry and build more of it, whatever your starting point. This is not about lifting as heavy as you can. It is about consistent, progressive resistance work that gives your body a reason to hold onto muscle instead of losing it. The muscle you build also supports your metabolism, which naturally shifts through this transition too, so the benefit reaches further than strength alone.

Why your bones need the same protection

Your bones respond to the same shift, for the same reason. Declining oestrogen makes this the period in your life when bone density is most vulnerable, which is why the years around perimenopause carry a higher long-term risk of osteoporosis. Weight-bearing and resistance training puts your bones under load, which is what tells your body to maintain and build density rather than lose it. This is not a reason to worry about your bones. It is a reason to train them now, while you have the most opportunity to make a difference.

What happens to your sleep and your mood

Sleep and mood are two of the areas people ask me about most. They deserve an honest answer rather than a dramatic one. Fluctuating hormones can disrupt sleep, particularly through night sweats. Around four in ten people going through perimenopause report sleep difficulty. Mood changes are real for some, but the research is more nuanced than it is often given credit for. Life stress, general health and your own history with mood all play a bigger role than hormones alone.

What we do know is that movement supports both. Regular training improves sleep quality and gives your nervous system a consistent outlet for stress, no matter what is driving it. 

There is also something reassuring in structure and consistency. Knowing what you are doing each week and showing up for it removes some of the uncertainty this transition can bring.

The best time to prepare is now

Perimenopause is not something to prepare for once symptoms arrive. The strength, bone density and resilience that carry you through this transition and beyond are built in the years before it, through consistent training that becomes part of how you live, not something you reach for in response to a problem.

This is what reDefine has been built for. It is the most Strength-focused Program we have ever created inside the LEAN App, 6 weeks combining Strength, Pilates and Cardio, with a Beginner or Intermediate / Advanced Program depending on your starting point. Whatever stage of life you are training for, building strength now is one of the most useful things you can do for the decades ahead.

Starting Monday 14 September. Join reDefine and let’s build it together.

Lilly