Let's drag one of the oldest meathead myths behind the gym and beat it unconscious with a kettlebell.

"I lift fast."

"I superset."

"I do MetCons."

"That's my cardio."

No, Brosefus, it's not.

That's like saying you trained grip because you rage-opened a pickle jar.

Or claiming you improved your vertical jump because you slipped on black ice outside Costco.

Something definitely happened.

It just wasn't the adaptation you paid for.

Your heart responds to exactly one thing:

The load you place on it.

Lifting and aerobic work simply hand it two completely different jobs.

Job #1: Pressure

Heavy lifting is a pressure problem.

Ever squat so hard your ancestors briefly appeared just to critique your depth?

That enormous brace keeps your spine happy.

Unfortunately, it also turns your chest into something with all the flexibility of a welded submarine hatch, forcing your heart to shove blood against a vascular system getting squeezed from every direction.

Cardiologists call this high afterload.

I call it trying to blast a Super Soaker through a garden hose somebody parked an F-350 on.

Your heart adapts by thickening its walls.

That's a legitimate adaptation.

A useful one.

The same thing as building a larger, better engine?

Not even remotely.

Job #2: Volume

Aerobic work flips the script.

Blood keeps returning to the heart. Venous return climbs, the chamber fills and stretches, and suddenly the Frank-Starling mechanism starts earning its paycheck.

Pack more blood into the chamber...

...and the next beat throws more blood out.

More stroke volume.

Lower resting heart rate.

Faster recovery.

More work before your lungs begin filing HR complaints.

That's the adaptation most lifters are secretly missing.

And before someone accuses me of inventing this after three espressos and too much time with a metabolic cart...

Sports cardiologists have been documenting these different cardiac adaptations between endurance and strength athletes for decades.

This isn't gym folklore.

It's cardiovascular physiology.

Here's where the internet drives straight into the ditch though...

People think because they're sweating...

...seeing stars...

...making noises normally heard during medieval torture...

...and questioning every life decision that led them to rep twelve...

...they must be building an aerobic engine.

Nope.

Sweat isn't the signal. Pain isn't the signal either, and heart rate by itself isn't the signal.

The loading condition is the signal.

Two workouts can leave you face-down on the rubber flooring contemplating your mortality...

...while producing completely different adaptations.

One upgrades the engine.

The other just upgrades your laundry bill.

Those are not the same thing.

So where do MetCons fit?

Before the CrossFit lawyers start warming up the cease-and-desist machine...

I like MetCons.

I program MetCons.

Flexible Meathead Cardio Level 2 happily wanders into that wonderfully miserable rabbit hole.

However, only using MetCons as your only form of cardio is like bolting a nitrous kit onto a rusted-out Honda Civic balanced on three bald tires and one cinder block.

Will something exciting happen?

Absolutely.

Will it end well?

History suggests otherwise.

Most people build a respectable glycolytic panic button mounted on top of an aerobic engine held together with expired BCAAs, electrical tape, and blind optimism.

Then they wonder why every workout turns into an out-of-body experience.

Recovery between sets stays lousy, your heart rate refuses to come down, every round feels twice as hard as it should, and somehow your "conditioning" never carries over.

The smoke got bigger.

The engine never did.

That's exactly why Flexible Meathead Cardio Level 1 exists.

Build the engine first.

Then go make questionable life choices at high intensity.

Flexible Meathead Cardio is $100 off through Monday night.

Use code CARDIO here:

​https://miket.me/cardio​

Much love, cardiac horsepower, and bigger engines,

Dr. Mike

PA - A chainsaw is an incredible tool.

So is a toothbrush.

Confusing the two usually ends with a trip to the emergency room.

MetCons are fantastic.

Building an aerobic engine is fantastic.

Just stop asking one to do the other's job.

Nerd receipts

• Baggish, A. L., & Wood, M. J. (2011). Athlete's heart and cardiovascular care of the athlete: Scientific and clinical update. Circulation, 123(23), 2723–2735.
• Morganroth, J., Maron, B. J., Henry, W. L., & Epstein, S. E. (1975). Comparative left ventricular dimensions in trained athletes. Annals of Internal Medicine, 82(4), 521–524.

The course is $100 off through Monday night with code CARDIO.

​https://miket.me/cardio​

Use CARDIO at checkout.

Mike T Nelson CISSN, CSCS, MSME, PhD
Associate Professor, Carrick Institute
Owner, Extreme Human Performance, LLC
Editorial Board Member, STRONG Fitness Mag

Mike T Nelson is a PhD and not a physician or registered dietitian. The contents of this email should not be taken as medical advice. It is not intended to diagnose, treat, cure, or prevent any health problem - nor is it intended to replace the advice of a physician. Always consult your physician or qualified health professional on any matters regarding your health.

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