The Minimum Effective Dose: Why Less Cardio Might Be the Smarter Move for Busy Moms over 35

New research says the minimum effective dose of cardio might be a fraction of what you think, and the data backs it up.

There is a version of you that exists only on paper. She wakes up early for Zone 2. She fits in two strength sessions and a HIIT workout without missing a single one. She has never once looked at her weekly plan and thought, there is no possible way I am doing all of this.

That woman is fictional. And chasing her is exactly what's been making fitness feel impossible.

The number that actually matters

Here's something worth knowing: your VO2 max, which is basically a measure of how efficiently your body uses oxygen, is one of the strongest predictors researchers have found for how long you're likely to live. A study following over 122,000 adults found that the fitter people were, the lower their risk of dying during the study period, and that benefit never leveled off. Not even at the highest levels of fitness measured.

So yes, this is worth caring about. But here's the part almost nobody tells you.

More was never actually the requirement

Somewhere along the way, we all absorbed the same unspoken rule: if it isn't long, hard, and exhausting, it doesn't count. Real cardio means an hour. Real training means five or six days a week. Anything less is just the warm-up version of a real plan.

The research says otherwise. In fact, one review pulled together 28 separate studies and found something almost funny: the size of the VO2 max improvement was basically the same whether people trained at low, moderate, or high intensity. The catch was that the higher intensity groups got there in significantly less total time.

In one twelve-week study, a group doing three 20-second all-out sprints inside a 10-minute session improved their fitness by exactly as much as a group doing 45 minutes of steady, moderate cardio, three times a week. Same result. A fifth of the time.

That's not a loophole. That's the actual data.

The permission you didn't know you needed

If you're a busy woman trying to hold down a job, a household, a body in perimenopause, and some version of a personal life, I want you to hear this clearly: the plan that fits into a real week is not the lesser plan. For a lot of us, it's the correct one.

This isn't about doing less because you've given up on your health. It's about doing therightless, backed by real, peer-reviewed research, instead of quietly burning out chasing a version of fitness that was never built for an actual human schedule.

Hear the full breakdown

In this week's episode, I walk through the research in detail, including the exact numbers, the studies behind them, and what this means specifically if you're navigating perimenopause. I also get honest about my own history with a color-coded workout calendar taped to my fridge, and what it took to let that go.

Listen to the full episode here

If you've been quietly exhausted by the idea that more is always the answer, this one's for you.