Cardio is a tool, not a punishment for eating. Used well, it supports a fat-loss deficit and your heart. Used badly, it torches the recovery your lifting needs.
How much cardio do you need for fat loss?
Fat loss is driven mainly by your calorie deficit, not cardio itself — cardio just helps widen and sustain it. A sensible base is the general activity guideline of 150–300 minutes of moderate (or 75–150 minutes of vigorous) activity per week, most of it easy steady-state, with a small, deliberate dose of intervals on top.
Steady-state vs intervals
| Steady-state (LISS) | Intervals (incl. HIIT) | |
|---|---|---|
| Effort | Easy, ~RPE 4–6 | Hard, ~RPE 8–9 |
| Recovery cost | Low; stackable | High; taxes lifting recovery |
| Time | Longer sessions | Time-efficient |
| Best for | Base volume, daily activity | A small, focused dose of fitness |
Intervals get you fit quickly but tax the recovery you also need for the gym; steady-state is gentler and easier to stack. Most people do best with a base of easy work and one or two short interval sessions — not a week of all-out HIIT.
Don't let cardio eat your lifting
The classic mistake is hard intervals the day before or right before heavy legs. Instead:
- Do hard intervals on a separate day from heavy leg training, or after lifting rather than before.
- Keep easy steady-state wherever it fits — walks count.
- In a deficit, remember conditioning supports the lifting that protects your muscle; it doesn't replace it.
A simple weekly template
- Daily: a floor of steps / easy movement.
- 2–3×/week: 20–40 min easy steady-state (RPE 4–6).
- 1–2×/week: short intervals (RPE 8–9), away from heavy legs.
- Adjust down if your strength or sleep starts sliding.
Effort and heart-rate targets
If you'd rather gauge intensity by numbers than feel:
- Easy steady-state: ~RPE 4–6; roughly 64–76% of max heart rate. Conversational pace.
- Hard intervals: ~RPE 8–9; roughly 77–95% of max. Talking gets difficult.
A rough max-heart-rate estimate is 220 minus your age — imperfect, but fine for setting zones. Most of your weekly minutes should sit in the easy band, with a small, deliberate dose up top. That balance is what lets conditioning support your deficit without stealing recovery from the gym.
Frequently asked questions
Is HIIT better than steady-state for fat loss? Neither is magic — total energy balance decides fat loss. HIIT is time-efficient but recovery-costly; steady-state is easy to sustain. A mix, weighted toward easy work, is the practical winner.
Should I do cardio before or after lifting? After, if it's the same session — so it doesn't blunt your strength work. Better yet, put hard cardio on separate days.
Can I lose fat without cardio? Yes, via diet and lifting alone. Cardio and daily steps just make the deficit easier and support your health.
Conditioning is one part of the system. It shows how to dose cardio by goal so it complements your lifting instead of competing with it. The full framework — the goal dials, the 4-day template, the exercise library with home substitutions, and the nutrition section — lives in The Adaptable Strength & Conditioning System, a $19 digital guide (reg. $29). It's education, not a prescription: it carries a health disclaimer and assumes you'll train sensibly.
External guidance: CDC physical activity guidelines. More in the Fitness & Nutrition library.