The best cardio for fat loss is the one you'll actually do consistently. That said, not all cardio is equal when it comes to preserving muscle, burning calories efficiently, and fitting into a lifting schedule.
The right type of cardio depends on your goals, schedule, and what you're already doing in the gym.
Cardio Types Ranked for Fat Loss
| Type | Cal/30 min | Muscle Impact | Recovery Cost | Best For |
|---|---|---|---|---|
| Walking (incline) | 150-250 | None | Very Low | Everyone, especially lifters in a cut |
| Cycling (low-moderate) | 200-350 | Minimal | Low | Easy on joints, pairs well with leg training |
| Rowing | 250-400 | Low | Moderate | Full body, calorie-efficient |
| Swimming | 250-400 | Minimal | Moderate | Joint-friendly, full body |
| HIIT | 300-500 | Moderate | High | Time-efficient, but limits lifting recovery |
| Running (steady state) | 300-450 | High | High | Runners who enjoy it, not ideal for lifters |
The Winner for Most People
Walking — specifically incline walking at 3-4 mph, 10-15% grade. It burns meaningful calories, doesn't interfere with lifting, requires zero recovery, and you can do it every day. Most competitive bodybuilders and physique athletes use walking as their primary cardio tool during cuts.
HIIT vs. LISS: The Real Comparison
The HIIT vs. steady-state debate has been going for years. Here's what the research actually shows:
| Factor | HIIT | LISS (Steady State) |
|---|---|---|
| Fat loss (same time) | Better | Good |
| Fat loss (same calories) | Equal | Equal |
| Muscle preservation | Good (short sprints) | Better |
| Recovery impact | High | Low |
| Time efficiency | Better | Slower |
| Sustainability | Harder to maintain | Easy to sustain |
Bottom line: When calories burned are equated, HIIT and LISS produce the same fat loss. HIIT is faster but harder to recover from. LISS is slower but sustainable and doesn't eat into your lifting gains. For lifters, LISS wins.
How Much Cardio Do You Need?
The answer depends on your calorie deficit strategy. Cardio is a tool to increase energy expenditure — not a requirement for fat loss.
Starting Point
- Steps: 8,000-10,000 daily (this alone burns 300-500 extra cal/day)
- Formal cardio: 2-3 sessions per week, 20-30 minutes
- Type: Walking, cycling, or rowing
When to Add More
- Weight loss stalls for 2+ weeks
- You don't want to reduce calories further (already at a comfortable floor)
- Add one session per week or increase duration by 10 minutes — don't jump from 2x to 6x overnight
Cardio + Lifting: How to Schedule
| Option | Schedule | Pros / Cons |
|---|---|---|
| Separate days | Lift Mon/Wed/Fri, Cardio Tue/Thu | Best for recovery, requires more gym visits |
| After lifting | Lift first, 20 min cardio after | Time-efficient, glycogen-depleted state |
| Morning fasted | 30 min walk AM, lift PM | Separates sessions, no performance impact |
If you lift 4+ days per week, the simplest approach is 20-30 minutes of walking on the treadmill after your lifting session. Done.
Common Cardio Mistakes During a Cut
- Starting with too much cardio. If you jump to 6 sessions/week on day one, you have nowhere to go when progress stalls. Start low, add gradually.
- Doing HIIT every day. HIIT is a stressor like lifting. Doing it daily trashes recovery, increases cortisol, and can cause overtraining. Limit to 2-3 sessions/week max.
- Relying on cardio instead of diet. You can't outrun your fork. A 30-minute run burns ~300 calories. One large cookie is 400. Diet does the heavy lifting; cardio assists.
- Eating back all exercise calories. Fitness trackers overestimate calorie burn by 20-40%. If your tracker says you burned 500, you probably burned 300-400.
- Ignoring daily steps. The 300 calories from 10,000 steps is more reliable and sustainable than formal cardio sessions. Walk more before adding gym cardio.
Frequently Asked Questions
Does cardio burn muscle?
Excessive cardio can interfere with muscle growth (the "interference effect"), but moderate cardio (walking, 2-3 sessions/week) doesn't. Keep protein high and lift hard — your muscles will be fine.
Is fasted cardio better for fat loss?
No meaningful difference. A 2014 study by Schoenfeld et al. found identical fat loss between fasted and fed cardio over 4 weeks. Do it whenever fits your schedule.
How many days of cardio per week?
Start with 2-3 formal sessions plus daily walking. Only increase if fat loss stalls and you don't want to drop calories further. Some people lose all the weight they need with just walking + lifting.
Should I do cardio before or after weights?
After. Lifting requires more coordination, focus, and glycogen. Doing cardio first will reduce your lifting performance. If you do both in one session, always lift first.
Track Your Cardio With AMUNIX
AMUNIX tracks both your lifting and cardio, connecting your training data with your nutrition to show you what's driving your progress.
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Consult a healthcare provider before starting any new exercise program.