The Power of Lactate Threshold Training: What It Is and Why It Matters

By Coach Dylan Belles

If you've ever glanced at your training schedule and seen the word "threshold" staring back at you, you're not alone in wondering, what exactly does that mean? In this post, I’m going to break down what threshold training really is, why it’s one of the most effective zones for endurance development, and how you can apply it practically to get faster, stronger, and stay healthier.

If you prefer, you can also listen to this topic, which I discussed in greater detail, here.

What Is Lactate Threshold?

Lactate threshold (LT) is the effort level where your body is producing and clearing lactate at a steady, balanced rate. It’s not a flat-out effort, nor is it easy — it’s that “comfortably hard” zone where you can sustain the work for roughly an hour. If you’re running mile repeats or a tempo workout and feel like you’re racing a 5K or 10k, chances are, you’re going too hard. True threshold training should feel challenging but manageable.

Physiologically, this effort sits around 83–88% of your VO₂ max for most trained athletes, or roughly 88–92% of your max heart rate. For less trained runners, it might sit a bit lower. But regardless of where your threshold lies, the key is that this pace allows you to do significant work without tipping over into exhaustion.

Why Runners Get It Wrong

One of the biggest mistakes runners make is pushing threshold workouts just a little too hard. The irony is that while this might feel like “good training,” it actually shifts you out of the threshold zone and into low-end interval territory — compromising the aerobic gains you’re aiming for.

In my early days, I was guilty of this. I’d hammer threshold runs like they were races, thinking I was getting tougher. In reality, I burned out, underperformed, and dealt with a cascade of overtraining issues. It wasn’t until I backed off, focused on control and consistency, and aimed for 85–90% instead of 100%, that I started seeing real, lasting improvements.

Why Threshold Training Works

Threshold training is so effective because it hits the sweet spot of aerobic adaptation. Here’s what it improves:

1. Muscle Fiber Efficiency

It trains both Type I (slow-twitch) and Type IIa (fast-twitch aerobic) muscle fibers to work longer without fatiguing. These fibers become more efficient at using oxygen and resisting fatigue — critical for both steady efforts and late-race surges.

2. Raises Your Aerobic Ceiling

While your VO₂ max determines your engine size, your lactate threshold determines how much of that engine you can use before redlining. Raising your threshold means you can run faster at a lower percentage of your max, making paces like marathon pace feel easier and more sustainable.

3. Improved Lactate Clearance

Lactate isn’t the villain many think it is — it’s actually a usable fuel. Threshold training improves your ability to transport lactate from fast-twitch to slow-twitch fibers and clear it efficiently before it builds up. Think of it as widening the drain in your sink: you can keep pouring water (effort) in without overflowing.

What the Norwegian Model Taught Us

The popularity of the “double threshold” approach from Norway — made famous by athletes like Jakob Ingebrigtsen — has shown us the potential of frequent, precise threshold sessions. These athletes train at threshold twice a day, multiple times a week, but keep their efforts tightly controlled. With lactate levels kept between 2–3 mmol/L, they avoid over-fatigue and instead build massive aerobic capacity over time.

While most of us aren’t training twice a day with lactate monitors, the takeaway is this: more controlled work at threshold can be incredibly powerful — if you're not tipping into interval territory.

Applying Threshold Training to Your Program

You don’t need fancy gear to benefit from threshold training. Here’s how to find the right effort:

• Talk test: You should be able to speak in 2–3 word phrases.

• Effort: Challenging but sustainable. You should feel like you could do 1–2 more reps at the end.

• Pacing: Roughly your 60-minute race pace — often between 10K and half marathon effort.

  
  

Example Workouts:

• 20 x 400m @ threshold (30 seconds recovery)

• 10 x 1K @ threshold (1-min recovery)

• 5 x 1.25 mile @ threshold pace (1.5-min jog recovery)

• 3 x 2 miles @ threshold (2-min jog recovery)

• 30–45 minute progression run ending at threshold
  

Start with about 20–30 minutes of total threshold work and gradually build toward 60 minutes over time. If you're doing a long session or integrating threshold into marathon training, be aware that the muscular and metabolic toll will be higher, and you'll need more recovery.

Why Marathoners Should Care

Threshold training is especially helpful for marathoners. It builds durable speed, improves fuel efficiency, spares glycogen, and makes marathon pace feel easier. It teaches your body to hold a strong, steady effort deep into a long run — so you’re not just surviving mile 20, you’re still racing it.

Final Thoughts: Keep It Controlled, Not Heroic

Threshold training isn’t sexy. It’s not flashy. It’s quiet, consistent work that pays off in big ways. If you walk away from your threshold workouts thinking, “I could have done a little more,” that’s a win, not a failure.

The goal isn’t to crush these sessions — it’s to build capacity. And over time, with enough of that work in the bank, you’ll find yourself running faster, feeling stronger, and recovering better than ever.

Got questions about threshold training? Drop them in the comments or shoot me a message — I’d love to chat. Until next time, keep putting in that good work.