Why Zone 2 Alone Won’t Cut It (And What Really Works for Women)

Let’s get real. If you’re still thinking that endless slow cardio is the way to get fit, it’s time to rethink.

Don’t get me wrong—Zone 2 has its place. It’s great for building aerobic fitness and supporting your mitochondria (those tiny energy factories in your cells). But here’s the thing: women are already built for endurance. We have more endurance muscle fibres, higher mitochondrial density, and oestrogen on our side to burn fat efficiently. Translation? We are naturally endurance queens.

So cruising along at a 'comfortable' pace week after week? Meh. It won’t challenge your body enough to protect your muscles, bones, metabolism—or even your brain—as you age.

Step It Up: Why Intensity Matters

This is where HIIT (High-Intensity Interval Training) and SIT (Sprint Interval Training) come in.

• HIIT: Short bursts (think 45 seconds to a few minutes) at near-max effort with equal rest.

• SIT: Even shorter, all-out sprints (20–30 seconds) with longer recovery (2–4 minutes).

Why bother? Because when you push past that 'comfortable' zone, your body adapts in ways slow cardio just can’t touch:

• Stronger heart and better cardiovascular fitness

• Improved insulin sensitivity and metabolism

• Maintenance of muscle and fast-twitch fibres (critical as we age)

• Support for bone density and overall hormonal balance

In short: intensity protects what matters most and keeps your body functioning like it should for decades to come.

Your Brain Loves HIIT Too

Here’s the kicker: the benefits aren’t just physical. Even one intense session can:

• Boost focus and mental clarity

• Improve memory and working attention

• Lift your mood and ease tension

• Support long-term brain health and resilience

That magic comes from BDNF (brain-derived neurotrophic factor), which promotes learning, neuroplasticity, and overall mental sharpness. Basically, HIIT isn’t just keeping you strong—it’s helping keep your brain sharp too.

How to Make It Work in Real Life

If your week is already packed with Zone 2 sessions, here’s an easy swap:

• Replace 1–2 Zone 2 workouts with HIIT or SIT

• Warm up properly before any sprints

• Pair intensity with recovery—sleep, rest, and downtime are where the gains actually happen

Quick examples:

• HIIT: 5 x 4 minutes (2 min hard, 2 min easy)

• SIT: 5 x 30 seconds all-out, 2–3 minutes rest

Simple. Brutal. Effective.

Bottom line: if you want to keep doing what you love—lifting, running, cycling, playing with your kids or grandkids, or just feeling capable in your own skin—you need more than slow cardio. HIIT and SIT give you a fitter body and a sharper brain, without wasting hours on the treadmill.

It’s science-backed, time-efficient, and honestly? You’re stronger than you think.

XO Jane