You’re sleeping terribly. Your jeans fit differently than they did six months ago — and you haven’t changed a thing. You’re irritable in ways that feel foreign to you, and your workouts feel harder even though you’re putting in the same effort. Sound familiar?
If you’re a woman in your late 30s, 40s, or early 50s, there’s a good chance what you’re experiencing has a name: perimenopause. And the frustrating part? Most women have never been told what it actually is — or that it could start this early.
We want to change that. This is the first blog in our five-part series on perimenopause, menopause, and what fitness actually looks like during this stage of life. We’re going to give you the science — clearly, without the overwhelm — and show you what’s possible when you understand what’s happening in your body and train accordingly.
First, Let’s Clarify the Terms
One of the biggest sources of confusion around menopause is that people use the word to mean everything — all the years of symptoms, the transition, the aftermath. But technically, these stages are distinct:
Perimenopause is the transitional phase before menopause. It can begin as early as your mid-30s — even earlier in some women — and typically lasts several years. Hormones fluctuate, cycles become irregular, and this is when most of the significant body composition changes begin.
Menopause is a single point in time: the day that marks 12 consecutive months without a menstrual period. That’s it. One day.
Postmenopause is everything that follows menopause — for the rest of your life. Hormones settle at a new, lower baseline, and with the right strategies, many women feel better than they did during the turbulent perimenopause years.
Why does this matter? Because the strategies that help you most depend heavily on which stage you’re in. And most of the conversation about ‘menopause’ is actually about perimenopause — the stage most women are actively living through but often can’t name.
What’s Actually Happening Hormonally
During your reproductive years, two hormones play lead roles: estrogen and progesterone. They rise and fall in a predictable rhythm across your monthly cycle, doing far more than managing reproduction.
Estrogen — specifically estradiol (E2) — supports tissue growth, bone health, blood glucose control, muscle contraction speed and strength, cardiovascular health, and cognitive function. It’s essentially a whole-body maintenance signal.
Progesterone is produced after ovulation by the corpus luteum, and it counterbalances estrogen. Together, they create a system the body relies on deeply.
During perimenopause, something shifts: ovulation becomes irregular, which means progesterone drops first and drops faster. This throws off the estrogen-progesterone ratio. Estrogen then fluctuates wildly — sometimes too high, sometimes too low — before it eventually declines. This hormonal turbulence is the root cause of most perimenopause symptoms.
The downstream effects show up everywhere: disrupted sleep, mood changes, brain fog, increased abdominal fat, reduced muscle mass, declining bone density, higher insulin resistance, and slower recovery from exercise.
When Does This Start? (Earlier Than You Think)
This is where many women feel blindsided. Perimenopause doesn’t wait until your late 40s. Dr. Stacy Sims, an exercise physiologist and nutrition scientist who has dedicated her career to women’s performance physiology, emphasizes that major body composition changes often begin 3 to 4 years before the final menstrual period — and perimenopause itself can begin a decade or more before that.
The signs are often subtle at first. A woman in her late 30s might notice her sleep worsening, a little more belly fat despite no changes in diet, or that she takes longer to bounce back from hard workouts. These aren’t signs of aging in some vague, inevitable sense. They’re often early hormonal signals — and they’re worth paying attention to.
So What Can You Actually Do?
Here’s what the research makes very clear: the way most women are told to exercise and eat during this phase of life is often the wrong approach. Conventional wisdom says eat less, do more cardio, and accept the changes. The science says something very different.
The most powerful tools available to you right now are:
Heavy resistance training — not light weights, not ‘toning.’ Lifting that challenges your neuromuscular system.
Power and plyometric training — jump training, explosive movements — to maintain bone density and nervous system firing speed.
Sprint interval training — short, hard efforts with full recovery — to restore metabolic flexibility and trigger hormonal responses that estrogen used to provide automatically.
None of these require being an athlete. They require being intentional. And starting sooner rather than later matters — perimenopause is actually the best window to build habits that will protect your health through menopause and into postmenopause.
We’ll go deep on each of these in the blogs ahead. But first, we want you to understand one more thing.
You Are Not Broken. Your Body Is Adapting.
One of the most common things we hear from women when they first learn about perimenopause is: ‘I thought I was just falling apart.’ The exhaustion, the weight changes, the mood swings — they assumed it was something they were doing wrong.
It’s not. It’s a significant biological transition — one that happens to roughly half the population and gets almost no attention in mainstream fitness culture. The tools to navigate it well exist. The research is clear. And you don’t have to figure it out alone.
That’s exactly why Coach Jaime created Muscles for Menopause here at MSP and FTX. Jaime is certified in Dr. Stacy Sims’ Menopause 2.0 methodology — one of the most evidence-based approaches to women’s training during perimenopause and menopause — and she brings that expertise into every class.
🏋️ Ready to train in a way that actually works for your body right now? Muscles for Menopause with Coach Jaime meets Tuesdays at 7:30pm and Saturdays at 10:00am. Classes are designed specifically for women in perimenopause and menopause — no experience required. Come try it and see how different it feels to train with your physiology, not against it.
Next up in this series: Why strength training — not cardio — is the single most important thing you can do for your body right now. We’ll explain the science in plain language and show you exactly what it looks like in practice.
