As a runner, you've probably heard the term VO₂ max thrown around in training discussions. Maybe you've even seen it on your smartwatch and wondered if it really matters for marathon training. Some coaches say it’s overrated, while others swear by it. So let’s break it down: what VO₂ max actually is, why it’s important for marathoners, and how you can improve it.
What is VO₂ Max?
VO₂ max, or maximal oxygen uptake, is the maximum amount of oxygen your body can use during intense exercise. It’s a key indicator of your aerobic capacity and endurance potential. The higher your VO₂ max, the more oxygen you can deliver to your muscles, which helps sustain performance over long distances.
Is VO₂ Max Important for Marathon Runners?
The short answer: yes, but it’s not everything.
Some coaches argue that VO₂ max isn’t as crucial for marathoners because other factors like running economy and lactate threshold play a bigger role in long-distance performance. It’s true that elite marathoners can still get faster even if their VO₂ max decreases slightly over time. However, for most runners, improving VO₂ max means increasing aerobic capacity, which is essential for marathon success.
Think of VO₂ max as your engine size. A bigger engine doesn’t guarantee a fast car, but it gives you the potential for speed if everything else (fuel efficiency, aerodynamics, etc.) is optimized. In the same way, VO₂ max alone won’t make you a better marathoner, but it sets the foundation for your endurance.
How to Measure VO₂ Max
Most runners measure VO₂ max in one of three ways:
- Lab Testing – The most accurate method, usually done on a treadmill while wearing a mask to measure oxygen intake.
- Field Tests – Time trials or maximal effort runs can estimate VO₂ max based on heart rate and pace.
- Wearable Technology – Watches from brands like Garmin, Coros, and Polar estimate VO₂ max based on heart rate and running data. These numbers aren’t perfect but can be useful for tracking trends.
How to Improve VO₂ Max
While genetics play a role in your VO₂ max, training can significantly improve it. Here’s how:
- High-Intensity Interval Training (HIIT) – Short bursts of hard efforts (like 400m or 800m repeats) push your aerobic capacity higher.
- VO₂ Max Workouts – Sessions at 95-100% of your max heart rate, such as 3-5 minute intervals at 5K pace with equal rest, are effective for improving VO₂ max.
- Long Runs – Increasing overall mileage and aerobic base strengthens your cardiovascular system.
- Hill Repeats – Running hard up hills builds strength and forces your body to use oxygen more efficiently.
Beyond VO₂ Max: Lactate Threshold and Running Economy
While VO₂ max is important, two other factors matter just as much for marathoners:
- Lactate Threshold – This is the pace at which lactate starts to accumulate in your blood. The higher your threshold, the faster you can run without fatiguing. You can improve this with tempo runs, steady-state workouts, and progression runs.
- Running Economy – This refers to how efficiently you use oxygen while running at a given pace. Strength training, drills, and proper running form all help improve running economy, making it easier to sustain marathon pace.
Why Periodization Matters
Training adaptation doesn’t happen overnight. Periodizing your training—meaning cycling through different phases like base building, intensity work, and tapering—helps maximize long-term improvements in VO₂ max, lactate threshold, and running economy. Instead of hammering the same workouts year-round, structured training allows your body to absorb stress, recover, and come back stronger.
Aerobic vs. Anaerobic Energy in Racing
Understanding how much of your energy comes from aerobic vs. anaerobic systems can help tailor your training. Here’s a general breakdown:
- 800m: ~40-50% aerobic, ~50-60% anaerobic
- 1,500m (Mile): ~65-75% aerobic, ~25-35% anaerobic
- 5K: ~85-90% aerobic, ~10-15% anaerobic
- 10K: ~90-95% aerobic, ~5-10% anaerobic
- Half Marathon: ~95-99% aerobic, ~1-5% anaerobic
- Marathon: ~98-99% aerobic, ~1-2% anaerobic
Marathon training should focus almost entirely on aerobic development, with just enough anaerobic work to sharpen speed and finishing power.
VO₂ max is a useful performance marker, but it’s just one piece of the puzzle. For marathon success, you also need to improve your lactate threshold, running economy, and aerobic efficiency. Structured training, strength work, and race-specific workouts will get you there.
If you’re serious about improving your marathon performance and want expert guidance tailored to your needs, I’d love to help. Whether you’re training for your first marathon or chasing a PR, we can build a plan that maximizes your strengths and helps you reach your goals. Let’s work together—because your best running is still ahead of you.