Feeling tired and sluggish? It’s not your metabolism — it’s your muscles.
- Shaini Verdon
- 2 days ago
- 5 min read
We hear it all the time — “My metabolism must have slowed down.”It’s what most women say when their body starts to change somewhere after 40. The jeans fit differently. Energy feels lower. Workouts that once felt easy now leave you wiped out.
And yet, you’re still eating well. You’re still moving. You’re not doing anything “wrong.”
But here’s the truth: it’s not that your metabolism has suddenly gone lazy. What’s actually changing is your muscle — the body’s most underrated metabolic organ.
Why we think it’s our metabolism
When women notice body composition shifts — a softer belly, less tone in the arms, fatigue that lingers — the first thought is always metabolism. We’ve been conditioned to believe it’s this mysterious internal fire that either burns brightly or fades away with age.
But metabolism isn’t a single switch that flips off when you turn forty. It’s the sum of what your body does to stay alive — breathing, digesting, moving, thinking, even rebuilding cells. And while resting metabolic rate does decline slightly with age, most of that change has far less to do with age itself than with the loss of muscle mass that tends to accompany it.
When we lose muscle, we lose the very tissue that keeps our body strong, stable, and metabolically active. In other words — the engine hasn’t failed; it’s simply shrinking.
Sarcopenia — the silent shift
There’s a name for this gradual loss of muscle: sarcopenia. It starts quietly, often from our mid-thirties, and accelerates every decade if we don’t challenge the body to rebuild. Research shows we can lose around 3–5% of muscle mass per decade after thirty — even faster during perimenopause and menopause.
Hormones play a role here. Oestrogen, beyond its reproductive functions, has a hand in muscle repair, collagen synthesis, and the way we use energy. As it begins to fluctuate, so does muscle quality and strength. Testosterone — yes, women have it too — also declines gradually, further reducing muscle tone and power output.
Together, these shifts explain why you might feel weaker, less stable, and more tired doing the same things you did easily a few years ago. Your metabolism hasn’t suddenly slowed — your muscle mass has quietly slipped away, taking your energy with it.
What happens when you lose muscle
Think of muscle as your body’s internal power grid. It burns energy, stabilises joints, stores glycogen, and communicates directly with your brain and immune system. When you lose it:
You burn fewer calories at rest.
Everyday tasks feel heavier.
Your blood sugar control worsens.
And your ability to recover from stress — physical or emotional — goes down.
That’s why feeling sluggish is so common in women during their forties. It’s not a lack of willpower. It’s biology asking for strength again.
How to wake up your metabolic engine
The good news? Muscle responds quickly when you start using it wisely. And that’s where training comes in — not the endless cardio kind, but intelligent strength training that meets you where you are and builds from there.
If you’ve ever taken one of my classes, you’ll know I always begin with squats. They’re simple, functional, and brilliant. Squats wake up the biggest muscles in your body — the glutes, hamstrings, quads, and deep stabilisers around your hips and spine. These are your metabolic powerhouses.
When you activate them, you do far more than tone your legs. You:
Stimulate large muscle groups that demand energy and oxygen.
Improve circulation and blood flow.
Send powerful hormonal signals that support repair and resilience.
In short — you turn the lights back on in your whole system.
Why the biggest muscles matter most
If you want to support your metabolism, start where your body holds the most potential: your large muscles. They require more effort, more oxygen, and more coordination, meaning your body has to work harder and adapt better.
Squats are one way in. So are deadlifts, lunges, push-ups, and rows — anything that challenges several joints and muscle chains at once.
It’s not about lifting the heaviest weight in the gym. It’s about progressive overload — giving your muscles a reason to grow stronger, whether that’s by slowing the tempo, adding resistance, or exploring balance and control in new ways.
This is where strength and intelligence meet — where movement becomes metabolic medicine.
What progressive overload really means
You might have heard the term progressive overload tossed around in fitness circles. It simply means: do a little more than before. Not recklessly more — just enough to signal your muscles that they’re needed.
For women 40+, that could mean:
Adding a few more reps.
Increasing load slightly (even a heavier kettlebell once a week).
Moving slower through the eccentric phase (the lowering part of a squat or push-up).
Introducing single-leg variations or more balance work.
Every small change counts, because it challenges the nervous system and stimulates muscle fibres to stay alive and responsive.
And the payoff? More muscle means more stability, better posture, stronger bones, and a metabolism that hums again — not because you’ve “fixed” it, but because you’ve fed it movement.
Training with intelligence, not punishment
I see so many women in this phase pushing harder with cardio, eating less, or blaming their hormones. But the answer isn’t punishment — it’s precision.
The moment you shift from trying to burn calories to trying to build strength, everything changes. You start to feel more capable, not just leaner. You recover faster. You sleep better. Your mood steadies.
And suddenly that sluggish feeling starts to fade.
Training this way doesn’t just support metabolism — it supports your nervous system, your bones, your confidence. It’s what I call intelligent strength — and it’s one of the most empowering things you can do in your forties and beyond.
A few practical steps to begin
If you’re new to strength training or returning after a break:
Start with form, not load. Learn the movement well before you add weight.
Prioritise large muscle groups. Do your squats, hinges, and pulls first in each session.
Mix in mobility and control. Use slow phases, pauses, and breath to connect strength with awareness.
Train 2–3 times per week. Consistency beats intensity.
Eat enough protein (and fibre). Your muscles need building blocks. Aim for protein at each meal, and hydrate well.
Rest and recover. Growth happens between sessions, not during them.
And above all — enjoy it. Feel what it’s like to inhabit a strong body again.
This isn’t about perfection
It’s not about sculpting the “ideal” physique. It’s about reclaiming your power — the inner fire that comes from feeling capable in your own skin.
Your metabolism isn’t broken. It just needs a reminder that you’re still here, still strong, still ready to move. And that reminder begins with your muscles.
Join me on YouTube
If you’d like to see what this looks like in practice, I’ve just shared a new video: “Feeling tired and sluggish? Start with squats.”It’s a short, functional sequence designed for women 40+, focusing on activating the big muscle groups that spark energy and rebuild strength from the inside out.
👉 Watch it on YouTube (if it's not online yet, come back in a few minutes as I am uploading it right now!)— and if it resonates, subscribe so you don’t miss the next movement session.
Your metabolism isn’t the problem. Your muscles are simply waiting for you to wake them up.
With love,
Shaini
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