Threshold Run Training Fixed What Zone 2 and VO2 Max Couldn’t

September 10, 2025 | By

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This is what the Maffetone Method says about my aerobic threshold: keep your heart rate under 137 beats per minute (180 minus your age). And this is what my lab test said: my lactate threshold doesn’t even start until 166 bpm.

In this episode, I’ll break down the difference between Zone 2, Threshold, and VO2 max and why they are all so important in helping improve your threshold so you can race and run faster.

I’ll also tell you about the very interesting results from my own test that flipped the script on Maffetone.

Listen to audio podcast below on your next run or watch the video above to learn more

What You’ll Learn

  • The critical differences between Zone 2, Threshold, and VO2 Max training and why they’re all essential pieces of your running performance puzzle
  • How my personal lab test results completely contradicted the Maffetone formula and what this means for your own training zones
  • The exact framework I’m using to incorporate threshold training effectively without burning out or plateauing

The Difference Between Zone 2, Threshold and Vo2 Max

Let’s start with definitions. Here’s the big picture:

Zone 2, Threshold, and VO2max are the three core gears in your training system.

Most runners use them wrong—or ignore one entirely—and then wonder why their race pace feels like a grind.

Zone 2: The Foundation

Zone 2 is your aerobic base builder. It’s easy, slow, and crucial. Arguably the most important.

You’re burning mostly fat for fuel, building mitochondria, and expanding your capacity.

It’s like your backpack. Build it right and strong and you can carry whatever tools you want in it to run fast; Vo2 max knife, threshold screwdriver, sprint and strides hammer, etc.

Threshold: The Critical Intensity

Threshold is the intensity where your body is at a metabolic tipping point – where lactate starts building up faster than your system can clear it.

You can sustain this effort for roughly 45-60 minutes at maximum.

In terms of racing, threshold pace typically corresponds to:

  • Half marathon to hour-long race efforts
  • Faster than marathon pace
  • Slower than 5K/10K race pace

Threshold training teaches your body to handle more lactic acid buildup, like upgrading your body’s waste removal system so you can run faster for longer.

Think of it this way: “Your muscles are a pot of water. Threshold is just before it boils over, makes a big mess and puts the fire out so you have to stop running.”

VO2max: The Peak

VO2max is your top-end aerobic power.

Short, sharp intervals. 80-90% of full gas. You’re training your body to use more oxygen per minute.

It’s like taking the governor off a race car. You’ll go faster—but only in bursts because it’s not sustainable.

The science: You’ve probably heard terms like “aerobic” (with oxygen) and “anaerobic” (without oxygen). People think aerobic = easy jogging and anaerobic = all-out sprinting. But here’s the twist: VO2max training is actually still aerobic! It’s just at the very upper limit of your aerobic system, where you’re burning through carbs (glycogen) super fast instead of fat. It’s like redlining your car’s engine – still using the same engine, just pushing it to its absolute max capacity.

“Your body has three training gears, but most runners only know how to use one.”

Fun Run Science Nerdy Facts And Things People Get Wrong

Here are four lactate facts that blew my mind:

#1 – Lactate isn’t bad—it’s actually fuel for runners. Your body always has some circulating, even at rest. The problem is when production exceeds your ability to use it.

#2 – That burning sensation during hard efforts? Not lactate itself, but hydrogen ions—the byproduct when you’ve got more lactate than you can handle.

#3 – “Lactic acid” is outdated terminology. It’s lactate, and we can train our bodies to tolerate more of it for longer.

I used to think lactate was related to milk (because of the Latin root “lac”). For years I imagined some milky substance pooling in my muscles during hard runs! Please tell me I’m not alone here!

So… how do you know where your zones are?

Most runners use a formula… I used Maffetone. I used it for years and it was great… but I had a gut feeling it may have been wrong.

So I got tested. And what I found… kind of destroyed that formula.

My VO2 Max & Lactate Threshold Test Results

Here’s what came back:

  • VO2 max: Slightly lower than 7 years ago year—but still in the “superior” range
  • Zone 2: From about 140 to 162 bpm
  • Threshold (LT2): Started at 166 bpms That means my “5k race pace zone” doesn’t even start until I hit 172 bpm.

Let that sink in.

I’ve spent the last few (13) years going deep into aerobic efficiency. Low heart rate training. Fat adaptation. Long slow runs. And it worked—I became really good at cruising.

But it came with a cost:

I stopped pushing into threshold territory altogether and when I did I wasn’t really at my true threshold.

I’ve basically built a high-efficiency diesel engine… that never gets tested at speed on the highway. Just cruising around side streets.

Note: You don’t have to run at threshold or higher, but doing a little bit here and there does help with overall Vo2 Max and life expectancy.

“Most runners waste time training by formulas instead of discovering their real threshold.”

Why This Matters for You

Okay—cool, that’s my data. But here’s why it matters for you:

If you’re using Maffetone—or just guesstimating your zones— You might be massively off from your real training intensities.

You could be undertraining. You could be overreaching. Or you could be like me—super fit, but accidentally avoiding the exact work that would move the needle.

Your real threshold isn’t a guess. It’s personal. Physiological. Trainable.

And once you know it—you stop wasting all your time in that “kinda hard, kinda useless” middle zone.

That middle zone is what I call “sub threshold” and it’s actually a way for you to improve your actual threshold with burning out.

What I’m Changing Based on the Test

Now that I know my zones? Here’s how I’m adjusting:

  • Adding weekly threshold or sub threshold sessions: cruise intervals, broken tempos
  • Reducing the “always easy” bias in my training
  • Periodizing: Zone 2 → Vo2 Max → Threshold → down weeks → repeat
  • Using objective and controlled data like my power meter on a treadmill, track or familiar flat-ish run route, to confirm effort—not replace intuition.

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