Should You Do Cardio Every Day?

When people want to lose fat faster, the instinct is almost always to add more cardio. Run more, bike more, get on the elliptical for an extra 30 minutes. I understand the logic — cardio burns calories, and burning more calories creates a bigger deficit. The problem is that the relationship between cardio and fat loss after 40 is more complicated than simple math, and more is not always better.

What Cardio Actually Does Well

Cardio done at the right intensity and volume does several useful things: it burns calories during the session, it improves cardiovascular health and insulin sensitivity, it reduces stress, and it supports recovery when the intensity is low enough. Walking is genuinely one of the best fat loss tools available — not because it burns enormous calories, but because it can be done daily without recovery cost, it lowers cortisol, and it keeps you active without eating into your ability to train hard.

The kind of cardio that gets people into trouble is high-intensity work done too frequently — daily HIIT classes, aggressive cycling programs, running 5–6 days a week on top of strength training. After 40, recovery capacity is a finite resource. Everything you spend on cardio is not available for strength training and muscle maintenance.

The Cortisol Problem After 40

High-intensity cardio every day significantly elevates cortisol — your body's primary stress hormone. Cortisol in short bursts is fine and useful. Chronically elevated cortisol promotes fat storage (specifically visceral, abdominal fat), suppresses testosterone, breaks down muscle tissue, and degrades sleep quality. After 40, cortisol management is not optional — it directly impacts every result you're chasing.

This is why I routinely see clients who are doing an hour of cardio 6 days a week who can't lose fat. Their cortisol is chronically elevated, their testosterone is suppressed, and their recovery is so impaired that their body is holding onto every calorie it can. They need less cardio, not more.

The Right Amount: A Practical Framework

Here's what I recommend for most adults over 40 who are doing strength training and want to optimize fat loss:

• Daily: Walking — 20–45 minutes. Low intensity, zero recovery cost, meaningful calorie burn over time, cortisol lowering. Do this every day without overthinking it.
• 2–3x per week: Zone 2 cardio — 30–45 minutes at 60–70% max heart rate. Conversational pace. Bike, treadmill incline walk, elliptical. This is where most of your cardio calories come from without significant interference with strength training.
• 1x per week maximum: High-intensity interval work — sprint intervals, cycling sprints, battle ropes. One session. High-intensity work has a role, but the recovery cost means once per week is usually the ceiling for people doing serious strength training.

Cardio and Strength Training: The Order Matters

If you're doing both in the same session, do strength training first — always. Cardio depletes glycogen and impairs the neural drive and force production your lifting demands. Lifting after cardio leads to compromised performance and slower strength gains. Cardio after lifting, by contrast, uses fat more readily as fuel and doesn't impair the strength training you already completed.

One thing to do today: if you're currently doing cardio 5 or more days a week and struggling to lose fat, replace two of those sessions with 30-minute walks and one with a strength training session. Give it four weeks and watch what happens.