Cardio for CrossFitters: Increasing Endurance for WODs

30 September 2025

So, you've finally admitted it—your Fran time is trash, Murph makes you want to fake an injury, and the only thing getting a workout during a long WOD is your excuse generator. Yep, we’ve all been there. You might be able to sling barbells around like Thor hurling his hammer, but when it comes to cardio? Oof. You gas out faster than your gym buddy's New Year resolution.

But fear not, burpee-hating brethren, because we’re about to open the Pandora’s box of cardio for CrossFitters. And yes, you’re going to need more than just a new playlist to get through it.

Why Cardio in CrossFit Isn’t Just Optional

Let’s get real for a second. CrossFit isn't just about lifting heavy or flipping tires like a caffeinated gorilla. It’s about surviving those soul-sucking Workouts of the Day (WODs) that seem like they were written by sadists with clipboards. You can have the squat depth of a Greek god, but if you’re wheezing like a pug at minute seven, what’s the point?

Cardio builds the endurance engine that lets you keep going—rep after miserable rep. It's like upgrading your body’s battery from a knockoff brand to a nuclear reactor. Want to RX your WODs without dying halfway through? You're gonna need lungs that perform like Teslas and not like rusted lawnmowers.

The CrossFit Cardio Conundrum: Why You’re Avoiding It

Let’s be honest. The word “cardio” to a CrossFitter often feels like someone just insulted your lifting technique. You grunt, shrug, and mumble something about “power output” while conveniently skipping those 800-meter runs.

Why? Because it sucks. Running is boring. Rowing is monotonous. And don’t even get me started on the Assault Bike—that tool of Satan disguised as fitness equipment.

But endurance is the peanut butter to your CrossFit jelly. It holds everything together. Without it, your performance falls apart faster than a Jenga tower on a wobbly table.

Know Thy Enemy: The 3 Types of Cardio You Need to Embrace (Even if You Hate Them)

Before you rage-quit this article and go back to bicep curls in the squat rack, hear me out. Not all cardio is created equal, and different types serve different purposes.

1. Low Intensity Steady State (LISS)

Think slow jogs, easy rowing, or biking while contemplating life’s biggest questions… like why you choose to do CrossFit in the first place.

LISS is great for active recovery and building your aerobic base—the foundation that lets you survive longer workouts without dying of embarrassment.

2. Moderate Intensity Continuous Training (MICT)

This is the “middle child” of cardio—often overlooked, but incredibly useful. We're talking about a steady, moderate pace for 20-40 minutes.

Perfect for gradually increasing endurance without frying your CNS (Central Nervous System, not Completely Numb Quads... though same energy).

3. High Intensity Interval Training (HIIT)

Ah yes, the golden-child of CrossFit cardio. Short bursts of all-out effort followed by brief recovery. Think sprints, Assault Bike sprints (a.k.a. the devil’s cardio), or EMOM-style workouts.

HIIT is brilliant for mimicking the intensity of WODs. It trains your heart to handle the chaos... sorta like preparing for Thanksgiving dinner with your in-laws.

Building the Engine: How to Integrate Cardio Without Losing Your Will to Live

Alright, now that we’ve accepted cardio as a necessary evil, how do we actually train it without wanting to join a knitting club instead?

Step 1: Start Slow. Like, Really Slow

Trying to go from zero to Murph without building a base is like trying to deadlift a truck without warming up. Spoiler: It ends in tears and probably a pulled hammy.

Start by adding just 2–3 low-intensity sessions per week. It could be a 30-minute bike ride, a casual row, or even a brisk walk with a vest if you want to feel fancy.

Step 2: Treat Your Heart Like a Muscle (Because It Is)

You wouldn’t max out your back squat every single day, right? (Please say no.) So don’t try to run sprints five times a week expecting magic.

Treat your cardio training with the same progressive overload mindset as strength training. Track your progress. Increase time, distance, or intensity gradually. Be the tortoise, not the sweaty rabbit faceplanting at minute six.

Step 3: Make It Fun. Or at Least Less Torturous

Don’t just stare at the wall while rowing, contemplating your life choices. Mix it up! Try partner runs, intervals with sandbags, or even throw in a game of ultimate frisbee with your gym buddies.

Cardio doesn't have to be a death march. If you're creative enough to suffer through 100 wall balls, you can definitely spice up a jog.

Cardio and the WOD: A Love-Hate Relationship

“But I already do cardio in my WODs!” you might say, trying to justify skipping that post-WOD run. Sure, WODs make you sweat. You pant. You cry a little. But doing cardio during a WOD isn't the same as actually training your aerobic capacity systematically.

It's like saying doing burpees means you’re practicing gymnastics. Technically true… but also hilariously wrong.

If you want to dominate those long WODs, not just survive them like a contestant on a game show, you need dedicated cardio sessions.

Programming Your Cardio Like a Boss

Here’s a sample weekly cardio schedule that won’t make you hate your life (too much):

Monday – LISS

- 30-min jog or bike ride (easy pace)
- Zone 2 heart rate (roughly 60-70% of max HR)
- Think: “Could I sing a bad karaoke song while doing this?” If yes, perfect.

Wednesday – MICT

- 25-35-minute row or mixed-modal cardio
- Keep your pace steady but challenging
- Add in some intervals every 5 mins to mix things up (e.g., 30 seconds hard pace)

Friday – HIIT

- 6 Rounds: 40s sprint / 20s rest on the Assault Bike
- Or EMOM:
- Minute 1: 15 cal row
- Minute 2: 10 burpees
- Minute 3: 15 wall balls
- Repeat for 5–6 cycles (yep, you’re welcome)

What About Running? Yes, You Have to Do It

Look, I get it. Running outside feels like a betrayal of your CrossFit box and your loyalty to bumper plates. But running is one of the simplest, most effective ways to build endurance.

Start small. Warm up, run 400 meters, walk 400 meters. Do that for 20 minutes. Boom: you’re building your engine. And bonus—running makes you better at just about everything that involves moving your body through space. Which, you know, is almost everything in CrossFit.

The Unsung Heroes: Rowers, Ski Ergs, and the Assault Bike

These aren't just machines… they’re portals to another dimension of pain and self-discovery. Embrace them.

- Use the rower for intervals and pacing.
- Ski Erg is great for upper-body endurance and pretending you’re in the Winter Olympics.
- The Assault Bike? It’s punishment and privilege wrapped into one steel-framed nightmare. Use it for HIIT, sprints, or when you need to humble yourself after talking trash during warm-ups.

Fueling Your Cardio Quest

Cardio training burns calories… and your soul. Make sure you’re fueling up properly so you don’t bonk 10 minutes in.

- Eat carbs. Yes, carbs are your friends, not the enemy your keto-loving coworker warned you about.
- Hydrate like it’s your part-time job.
- Don’t try to train on empty unless you like hallucinating halfway through a run and fist-fighting imaginary opponents.

Rest, Recovery, and Not Being a Wreck

The only thing worse than no cardio is too much cardio with no recovery. You’re not a robot (yet). Give your body time to adapt, rebuild, and not hate you.

- Prioritize sleep over scrolling through mobility memes.
- Mobility work isn’t optional if you want your joints to last longer than your protein powder.
- Take rest days. Seriously, you're not weak—you're smart.

Final Thoughts: Cardio Isn’t Just for Runners in Tiny Shorts

If you want to crush WODs, dominate comps, or just not look like a tomato at the 8-minute mark, adding intentional cardio to your training is the cheat code.

You don’t need to become a marathon runner or start wearing a heart rate monitor like it's a badge of honor—but you do need to respect the process.

Cardio doesn’t steal your gains. Bad programming and ego-lifting do. Build that engine, keep your strength, and maybe—just maybe—smile the next time Murph rolls around. (Okay, that might be pushing it.)

So lace up those kicks, press start on the rower, or hop on the bike—and remember: cardio isn’t your enemy. Mediocrity is.