If you’ve ever seen your VO₂ max score on your watch, you might wonder how much it actually matters. While VO₂ max is an important measure of aerobic fitness, it isn’t the best predictor of race performance on its own. Two runners can have identical VO₂ max values but perform very differently on race day. That’s because running performance depends on more than just how much oxygen your body can use.

Three key factors work together to determine how fast you can run: VO₂ max, running economy, and lactate threshold. Understanding each one can help you train smarter and get more from every workout.

VO₂ Max: The Size of Your Engine

Think of VO₂ max as the size of your aerobic engine. It measures the maximum amount of oxygen your body can take in and use during intense exercise. While genetics largely determine your ultimate ceiling, most runners never reach their full potential without consistent training.

As your aerobic fitness improves through regular running and structured workouts, your VO₂ max can increase—up to your individual limit. Beyond that point, improvements in race performance usually come from becoming more efficient rather than simply increasing your VO₂ max.

Running Economy: Getting More Speed From the Same Engine

Running economy is how efficiently you use your aerobic engine. Two runners may have the same VO₂ max, but if one uses less energy to run the same pace, they’ll almost always perform better.

Running economy improves through consistent mileage, good mechanics, strides, short fast repetitions, hill sprints, and strength training. Over time, your body learns to waste less energy with every stride, allowing you to run faster without working harder. More speed for the same effort.

Lactate Threshold: Holding a Faster Pace Longer

Lactate threshold refers to the fastest pace you can sustain before fatigue begins to build rapidly. As your running speed increases, lactate production eventually outpaces your body’s ability to clear it. Improving your lactate threshold allows you to maintain faster paces for longer before that tipping point occurs.

This is one of the biggest predictors of success in races from the 10K through the marathon.

Three Pillars of Fitness

Think of these three systems working together.

• VO₂ max determines the size of your engine.
• Running economy determines how efficiently you use that engine.
• Lactate threshold determines how much of that engine you can sustain during a race.

Improving just one area can make you faster, but the greatest gains come from developing all three over time.

Which Should You Focus On?

The short answer? All of them. The good news is that most well-designed training plans naturally develop each system. Easy runs build your aerobic base. Tempo runs improve lactate threshold. Interval workouts target VO₂ max. Strides, hill sprints, and strength training improve running economy.

Many workouts also provide overlap. For example, fast interval sessions can improve both VO₂ max and running economy, while tempo runs reinforce aerobic efficiency as well as lactate threshold.

How to Improve All Three

If you are looking for more specific workouts that focus on an area you are lacking, try some of these strategies to improve your running economy, lactate threshold, and VO₂ max.

• VO₂ max – Interval workouts (3-5 minute repeats), aerobic mileage, long runs
• Lactate – Tempo runs, cruise intervals, threshold workouts
• Running economy – Consistent mileage, strides, hill sprints, short fast repetitions, strength training

While VO₂ max often gets the spotlight, it tells only part of the story. Becoming a faster runner is about using your aerobic engine efficiently and sustaining a high percentage of its capacity for as long as possible.

The best training plans don’t chase one metric. They systematically develop all three. By consistently training your aerobic system, improving your running economy, and raising your lactate threshold, you’ll become a stronger, more efficient runner and see the results where they matter most—on race day.

Want training that develops all three systems at the right time? At Fast Pack Running, we build personalized training plans that take the guesswork out of improving your fitness. Whether you’re chasing a new 5K PR or preparing for your next marathon, we’re here to help you train smarter. Subscribe to our Training Tips newsletter for weekly coaching insights, or reach out to learn more about our custom coaching options.