Does Cardio KILL Your Gains?
Or is avoiding cardio stopping you from becoming Lethal?
Cardio doesn’t kill your gains.
It’s an essential piece to become Lethal.
We’ve seen this myth shattered over & over again over the last decade.
More men are realising that you can build an elite gas tank & still have an impressive physique.
Hybrid athletes (Nick Bare), modern runners (George Heaton) & fighters (Anthony Joshua) are all hard, concrete evidence that you can have a 1% physique, whilst also building an elite gas tank at the same time.
This myth exists because most men fundamentally misunderstand the relationship between building a gas tank & building muscle.
They believe its one or the other & you can’t have both.
The issue isn’t doing cardio.
The issue is a dumb training system.
This piece is going to obliterate any belief that cardio kills your gains & give you actionable steps to build your physique & gas tank simultaneously.
CARDIO DOESN’T KILL YOUR GAINS.
YOU DO.
Most lifters blame cardio for their stagnation because they misunderstand how muscle actually grows.
If you blame cardio for your lack of progress, you’re looking at the wrong target.
These are the 4 most common ways that muscle gain will plateau:
Poor Recovery: You train like an animal but sleep 5 hours and scroll till 2AM. Muscle builds during recovery. Own your sleep quality.
Sub-Par Nutrition: Your muscles aren't stalling from cardio; they're starving from inadequate fuel. Plus, cardio improves nutrient delivery through enhanced blood flow—the highway for your gains.
Limited Work Capacity: You gas out after 5 reps of squats? That's not cardio stealing gains—that's lack of cardio holding you back. Your heart and lungs drive your training. Small engine, small performance.
No Structured Plan: Random training without a coherent program produces random results. It's not the cardio's fault—it's your haphazard approach.
If your recovery, nutrition, base work capacity & training protocol are intelligent, cardio should enhance your gains, not take away from them….. here’s why:
HOW CARDIO ENHANCES YOUR GAINS
Cardio, when done right, can actually accelerate your muscle and strength gains. Yes, read that again.
We're not talking marathons or hours on the elliptical. We're talking strategic, performance-oriented conditioning. Here's 5 ways cardio amplifies your gains:
1- Improved Blood Flow & Capillarization:
Cardio strengthens your heart and expands your blood vessel network. More blood flow means more oxygen and nutrients rushing to your muscles. The result? Faster recovery between sets and workouts.
2- Greater Work Capacity & Endurance:
Regular cardio boosts your VO2 max and mitochondrial density - your body becomes more efficient at producing energy. This translates to higher work capacity in the gym. You'll squeeze out extra reps, sets, or even additional exercises because you're not gassing out. Over time, those extra efforts compound into greater gains.
3- Enhanced Nutrient Partitioning:
Regular conditioning improves insulin sensitivity, shuttling more nutrients toward muscle cells instead of fat storage. Cardio also modulates hormones positively - low intensity cardio can reduce chronic cortisol levels while HIIT stimulates growth hormone release. Rather than being catabolic, strategic cardio makes your body a more efficient muscle-building machine.
4- Increased Mitochondrial Density:
Cardio encourages your body to create more mitochondria and make them more effective. More mitochondria mean your muscles generate energy more efficiently for heavy lifts and high-volume sessions. Your aerobic system helps recharge your ATP-PC system between sets, meaning you recover faster and hit each set harder.
5- Faster Recovery & Reduced Soreness:
Light cardio increases blood flow and reduces DOMS by clearing metabolites. By incorporating gentle cardio on rest days, you accelerate recovery. You'll come back to the weights fresher and sooner than if you just sat on the couch.
Cardio isn't kryptonite to your gains - it's your overlooked ally. So the next time someone says "cardio kills gains," remember: that mindset is stuck in the stone age.
HOW TO IMPLEMENT CARDIO WITHOUT KILLING YOUR GAINS
Now that you understand why cardio amplifies rather than kills your gains, let's cover exactly how to implement it within your training protocol:
THE 3-TIER IMPLEMENTATION SYSTEM
For maximum muscle retention (and growth) while developing your gas tank, structure your cardio across these three tiers:
TIER 1: BUILD YOUR METABOLIC BASE (2-3x WEEKLY)
This foundational work creates the physiological infrastructure for everything else:
Daily Walking: 30-60 minutes at a conversational pace. This improves blood flow, enhances recovery, and burns fat without taxing your recovery systems. Do this on rest days or after lifting.
Low-Impact Steady State: Cycling or swimming for 30-45 minutes at 120-140 BPM. These modalities provide cardiovascular stimulus without the joint stress that can interfere with lifting recovery.
ELITE TIP: Schedule these sessions as far from your heaviest lifting days as possible. If you train legs hard on Monday, your low-impact steady state is best on Wednesday or Thursday.
TIER 2: SKILL-BASED CONDITIONING (1-2x WEEKLY)
This is where you make cardio enjoyable while developing real-world capability:
Martial Arts Training: Boxing, Muay Thai, BJJ, or MMA provides high-intensity intervals naturally embedded in skill acquisition. The rotational power development also transfers directly to lifting.
Recreational Sports: Basketball, tennis, or pick-up soccer all develop stop-and-go conditioning that mimics life's actual demands.
PROGRAMMING TIP: Place these sessions on the same day as upper body training (never before heavy leg days), and separate them by at least 6 hours to minimize interference.
TIER 3: PRECISION CONDITIONING (1x WEEKLY)
This is the sharpening stone for those seeking elite gas tank development:
High-Output Intervals: 30-60 second all-out efforts on an assault bike, rower, or sprints with 3-5 minutes full recovery between efforts.
Energy System Development: Just 4-8 minutes of total work at this intensity produces dramatic adaptations while minimising recovery cost.
KEY PRINCIPLE: Maintain even effort throughout each interval—the power output in the first 5 seconds should match the last 5 seconds. This prevents the "crash and burn" pattern that makes cardio feel miserable.
THE NON-NEGOTIABLES FOR
PREVENTING MUSCLE LOSS
When implementing this system, adhere to these principles to ensure cardio enhances rather than hinders your gains:
Modality matters: Cycling causes 30% less interference effect than running.
Timing: Separate cardio and lifting sessions by 6+ hours when possible.
Intensity: Use zone 2 cardio (<75% max HR) for recovery benefits.
Nutrition: Consume 20-40g protein within 2 hours post-cardio to promote muscle building (muscle protein synthesis).
Cardio doesn't kill gains when implemented strategically. This system ensures you develop both simultaneously, creating not just a better physique, but a truly capable one.
REDEFINING THE MEANING OF “GAINS”
The fitness industry has conditioned you to measure gains exclusively through muscle mass: more inches on your arms, more weight on the bar, more size on your frame.
But this narrow definition misses the bigger picture.
True gains aren't just about muscle tissue. They're about expanding your physical capital, a currency as valuable as the money in your account.
Physical capital gives you options. Freedom. The ability to say yes when others must say no.
Consider this: What good is that extra inch on your biceps if you:
Can't climb three flights of stairs without gasping for air
Need to decline spontaneous activities because your conditioning won't support them
Can't protect yourself or loved ones in a crisis requiring sustained output
Struggle to maintain focus during long workdays due to poor cardiovascular health
An elite gas tank and developed cardiovascular system multiply your gains across every domain of life.
This is the essence of the Lethal Gentleman approach—developing complete physical capacity that transfers to every aspect of your life. Not just looking capable, but being capable.
That's why I've dedicated my career to helping men build this kind of comprehensive physical capital. Not just aesthetic muscle, but genuine, transferable capability.
THE JOURNEY TO BECOMING LETHAL STARTS HERE:
1. THE LETHAL GENTLEMAN PROTOCOL
The complete system to develop strength, power, mobility, and conditioning simultaneously—engineered for the 1% physique that performs as good as it looks.
2. THE VO2 MAXXING BLUEPRINT
My proven 3-tier system to build an elite gas tank that enhances your gains rather than compromising them.
3. BESPOKE & CUSTOMIZED PROGRAMMING
Paid Substack members can work with me 1-on-1 to turn you into Bruce Wayne in a year. DM me on Substack if interested.
Be Lethal.
J.Krucial
Your reflective questions regarding physical performance across domains, especially when it comes to supporting our loved ones, are the best