Cardio Mistakes Women 40+ Are Making

Why is it that so many women in their 40s and 50s are pounding the pavement, spinning themselves into oblivion, and signing up for back-to-back bootcamps… only to feel utterly wrecked, wired, and still wondering why the midsection refuses to budge?

Dr. Stacy Sims’ latest video — Cardio Mistakes Women 40+ Make: Cortisol, Fatigue & Belly Fat  — gets straight to the heart of it. And it’s not what most of us were brought up believing.

The Cardio Con

Exercise is a stress. A good stress, if we use it wisely. We don’t get fitter during the workout — we get fitter in recovery. But once oestrogen and progesterone start to leave the stage, the way our bodies respond to that stress changes.

Here’s the science in plain English:

• Long, moderate cardio (that 'smash yourself but not quite vomit' zone) is the worst of both worlds. Too intense to be easy, not intense enough to spark the big hormonal shifts we need.

• Instead of building resilience, it keeps cortisol simmering — hello fatigue, poor sleep, and the dreaded “I’m doing everything but my belly fat won’t budge” complaints.

• In short: that endless treadmill jog, weekly spinathon, or four-day-a-week Orange Theory or F45 habit isn’t helping your hormones, your energy, or your waistline.

Why Sweating Buckets Doesn't Shift Belly Fat

Us meno ladies were raised in the era of step aerobics marathons and 90-minute 'fat burning' classes. The message was: if you’re not dripping in sweat, you haven’t worked hard enough.

Sound familiar? The bucket-in-the-corner, 'if you’re not spewing, you’re not trying' mentality.

The problem is that in peri- and post-menopause, more isn’t better. More is just… well, more stress. And our bodies don’t thank us for it.

The Goldilocks Zone Is a Trap

That moderate zone 3–4 — the one most gym classes and cardio machines love to keep us in — is catabolic. It eats into muscle glycogen, leaves you hungry, drives up cortisol, and doesn’t stimulate the anabolic (rebuilding) response we desperately need in midlife.

That’s why women often say:

“I do spin three times a week, plus a couple of jogs, and I’m exhausted. Why isn’t it working?”

Because the body is stressed but not challenged in the right way. It’s not you. It’s the programming.

What Actually Works (Nope, It’s Not More Cardio)

Dr. Sims explains that midlife women thrive on polarised training: spending time at the ends of the intensity spectrum and ditching the middle mush.

• Zone 1–2 (Low & Lovely): Brisk walks, hikes, light mobility. Supports heart health, clears the head, and lowers cortisol.

• Zone 5 (High & Hot): True high-intensity intervals — 20–60 seconds of effort, then full recovery. These short bursts trigger growth hormone and testosterone, build resilience, and keep metabolism humming.

• Strength Training: The non-negotiable pillar. Heavy, purposeful lifting maintains lean muscle, strengthens bones, and keeps your metabolism alive and well.

Together, these give your body the 'good stress' it needs to adapt, without keeping you in a constant state of cortisol soup.

What This Looks Like in Real Life

Here’s how to stop flogging yourself into the ground and actually get results:

• Swap your 60-minute treadmill grind for a 25-minute walk with purpose (bonus points if it’s outdoors with a podcast you love).

• Add 2–3 strength sessions a week — enough weight that rep 8 feels challenging. This is your hormone replacement in barbell form.

• Slot in 1–2 spicy interval sessions: short, sharp, with proper recovery. Think 30 seconds on, two minutes off.

• Keep a 'soul food' session — your step class, long bike ride, or Dancefit class (why I'm an instructor these days) — not for fat burn, but for joy. Because exercise should feel good too.

Quality Over Quantity

This might be the hardest mindset shift: shorter, smarter workouts are not a cop-out. In fact, they’re more effective. A focused 25–30 minute session with polarised intensity beats an hour of grey-zone cardio every single time.

And yes, it’s tough to shake the 'more is better' voice in your head. But the science is clear, and so are the results.

The Bottom Line

If you’ve been smashing yourself with endless cardio and getting nowhere, it’s not because you’re lazy, broken, or 'too old.' It’s because your training needs have changed — and no one bothered to tell you.

Midlife fitness isn’t about flogging yourself. It’s about choosing the right stress, building resilience, and letting recovery do its magic.

So, next time you’re tempted to double up on cardio, remember: your hormones will thank you more for heavy lifting, polarised intensity, and a good night’s sleep.

And if you want to hear it from the expert herself, watch Dr. Stacy Sims’ video here:
👉 Cardio Mistakes Women 40+ Make: Cortisol, Fatigue & Belly Fat

XO Jane