If lifting is how you shape your body, cardio is how you run it.
Your engine work. And before you roll your eyes, understand this: cardio isn't just about fat loss. It's about how well your body performs, recovers, and handles everything else you throw at it.
Most people are stuck at two extremes. Either they completely avoid cardio because they're scared of losing gains, or they overdo it and burn through muscle because they don't understand how to use it.
Cardio, when done right, makes everything else easier. Your recovery, your appetite control, your sleep, even your pumps in the gym. So let's break it down properly.
What Cardio Actually Does
Cardio improves your cardiovascular efficiency — how well your heart pumps blood and how efficiently your body moves oxygen and nutrients.
When your heart and lungs work better, everything in your body works better. You recover faster between sets. You sleep deeper. Your work capacity goes up. You can handle more training volume.
Even if you don't care about endurance, cardio still matters. Think of it like upgrading your car's engine before tuning the body. You can't have peak performance on a weak foundation.
LISS vs HIIT: The Two Tools
There are two main styles of cardio worth caring about: LISS and HIIT. Each does something different, and you use them for different goals.
LISS is Low Intensity Steady State. Walking, incline treadmill, cycling, light jogging. You can breathe through your nose the whole time. Burns fat directly, doesn't tax recovery. Can be done almost every day.
HIIT is High Intensity Interval Training. Sprints, circuits, assault bike intervals, hill runs. You're near max effort for short bursts. Great for conditioning and metabolic health. Very taxing on recovery — limit to 1–2 sessions a week.
You don't have to pick one or the other. Think of LISS as your base, something you can do all the time. HIIT is the seasoning.
The Role of Cardio in Fat Loss
Cardio doesn't make you lose fat. A calorie deficit does.
But cardio helps by creating that deficit without dropping your food too low. It's an energy balance tool, not the main event.
Start with 3–4 sessions of LISS per week at 30–45 minutes each. Keep your daily step count above 8–10k. Add a HIIT day if you like intensity or need to break through a plateau.
The key is to use cardio to support your deficit, not to chase calories burned. Your diet controls the fat loss. Cardio just speeds up the process a bit.
Cardio and Muscle Retention
You won't lose muscle from cardio. You'll lose muscle from under-eating and not lifting properly.
What kills muscle is energy mismanagement, not the treadmill. Cardio actually supports muscle retention if you keep training and eating enough protein. It improves nutrient delivery, helps with recovery, and keeps your metabolism high while you're cutting.
What matters is how you do it. Don't combine intense cardio and heavy lifting in the same session. Separate them by 6+ hours or put cardio on rest days. Keep HIIT sessions short, 15–20 minutes max. Always eat something after if you're in a deficit.
Conditioning vs "Cardio"
Conditioning is what you build on top of cardio. It's your body's ability to perform under fatigue — not just move for a long time, but move well and stay sharp.
Cardio builds endurance. Conditioning builds performance.
Example: a 40-minute walk is cardio. A 10-round kettlebell circuit with rest control is conditioning.
Conditioning is the overlap between strength and endurance. It's what makes your physique look athletic instead of just aesthetic.
Programming Cardio Around Lifting
Here's where most people screw up. They either train cardio too close to lifting or do way too much of it during a cut.
You have three good options. First is separate days — cardio on rest days, ideal for maintaining recovery. Second is after lifting — do LISS cardio after your lift, not before, so it keeps your gym performance unaffected. Third is different times of day — lift in the morning, cardio in the evening, or vice versa.
Never do heavy lifting and HIIT back to back. That's how you ruin recovery and performance.
How Much Cardio You Actually Need
It depends on your goal.
If you're bulking, stick to 1–2 LISS sessions per week to keep appetite and fitness up. If you're recomping, do 3–4 LISS sessions plus one HIIT. If you're cutting, scale up to 4–6 LISS sessions and 1–2 HIIT if recovery allows.
Cardio isn't a punishment. It's part of the system. You scale it up or down depending on your calories and recovery, just like you'd adjust volume in the gym.
The "Too Much Cardio" Problem
You'll know you're overdoing it if strength starts dropping across multiple lifts, you feel flat and depleted and unmotivated, or you're constantly sore even though you're not training more.
Cardio burns calories, but it also burns through recovery resources. You only have so much energy to recover from. Don't waste it all on the treadmill.
If that happens, pull cardio back by 1–2 sessions or eat a bit more food. Always protect your lifting performance first.
How to Make Cardio Actually Sustainable
Most people quit cardio because they make it miserable. They pick a form they hate, do it too hard, and think it's supposed to feel like punishment.
Pick a method you don't dread. Walking, incline treadmill, cycling — whatever feels easiest to start. Do it at the same time every day. Treat it like brushing your teeth. Listen to podcasts, music, or voice notes. It's not supposed to be spiritual, just consistent.
The best cardio is the kind you can do forever without thinking about it.
Conditioning Workouts That Actually Help
Here are a few examples that improve conditioning without wrecking recovery.
Sled pushes or farmer carries done for 3–4 rounds at 30–40 seconds of work followed by 90 seconds of rest. Builds work capacity, grip, and legs simultaneously.
Assault bike intervals at 10 rounds of 20 seconds hard followed by 100 seconds easy. Simple, brutal, efficient.
Weighted step-ups or hill sprints at 8–10 sets of 30–40 seconds work followed by 2 minutes rest. Great blend of lower-body strength and cardio conditioning.
Keep conditioning under 20–25 minutes total. Treat it like training, not punishment.
Cardio & Hormones
Cardio improves insulin sensitivity, reduces inflammation, and supports better hormonal health when done in moderation.
But overdoing it — especially HIIT — can spike cortisol and make fat loss harder long-term. Balance is everything.
If you feel wired but tired, sleep worse, or lose your appetite, you're doing too much. Cardio should make you feel better, not worse.
The Real-World Routine
Here's a simple template that works for almost everyone.
Monday you lift and add 30 minutes of LISS. Tuesday you lift and get your steps in, over 10k if possible. Wednesday is a HIIT day at 15 minutes plus some mobility work. Thursday you lift again with 30 minutes of LISS. Friday is another lift day with steps. Saturday is 45 minutes of LISS or a long outdoor walk. Sunday is rest or a light walk.
That's a complete cardio setup. You're hitting conditioning, recovery, and endurance without burning out.
Cardio isn't the enemy of muscle. It's the support system that lets you train harder, recover faster, and stay leaner.
It builds endurance, sharpens your physique, and keeps your engine healthy. You don't need to do hours of it. You just need enough of it — consistently — to keep your system running efficiently.
Lift to build. Cardio to maintain. Both to last.
Action Items
**This Week:**
1. Add one LISS session. Pick the easiest form of cardio for you — walking on an incline treadmill, cycling, whatever doesn't make you want to quit. Do 30 minutes after one of your lifts this week. Just one session. See how it feels.
2. Track your daily steps. Use your phone or watch. Check your average over the next 7 days. If it's under 8k, that's your new baseline target. You don't need to hit it overnight, just start moving more throughout the day.
3. Separate your cardio from heavy lifting. If you've been doing HIIT before squats or deadlifts, stop. Move cardio to after lifting, on rest days, or at a completely different time of day. Your strength will thank you.
**Quick Win (Do This Tomorrow):**
Go for a 20-minute walk after dinner. No music, no distractions. Just walk. It'll help digestion, clear your head, and count toward your daily steps. This is the easiest cardio habit you can build, and it compounds over time.
Next Chapter Preview:
We'll cover building the fitness identity — how to make training a permanent part of who you are instead of something you force yourself to do. This is where most people fail long-term, and it's entirely fixable.