VO₂max: Your Aerobic Ceiling

What it predicts

In well-trained runners, a 2022 review concluded that the speed at VO₂max seems the best predictor of performance at 1500 m, and that the blood lactate response takes over from 5000 m up to the ultramarathon¹. So VO₂max work earns its place most for the mile to the 5K. For longer races it is one of three things that set your speed, with lactate threshold and running economy as the other two, and most of the training that builds it is easy running.

What raises it

Easy volume and hard intervals both raise it, and the first lever to pull depends on your history. A newer runner, or one whose running is mostly hard or moderate, gains most from more easy running (see the guide on the aerobic system). A runner with years of high volume and almost no true intervals has more to gain from adding them over several months while keeping the volume.

Response to the same training differs between people, and between blocks in the same person. In 42 untrained adults who completed the same 8-week program twice, each person's gains were poorly reproducible from one block to the next². A block that raised nothing does not make you a non-responder, and a block that worked is not a promise the next one will. The study was of untrained adults, not runners.

A 2025 meta-analysis of nine randomized trials in endurance runners found that continuous moderate-intensity training raised VO₂max more than interval training did, while interval training did better for running economy³. Intervals and continuous running do different jobs, which is a reason to keep both and not to swap one for the other.

How to run VO₂max intervals

A session counts when it spends enough time near the ceiling. The target is more than 12 minutes in total above about 90% of VO₂max (10 minutes for a runner early in training), in reps of 1 to 4 minutes, which is about 10K to 5K race effort. A good session for most runners holds 10 to 25 minutes of hard running in total. A newer runner gets there in steps: strides first, then bite-sized work such as 6 reps of 2 or 3 minutes, and does not need the full dose.

Keep reps to three minutes or under for most sessions. At three minutes or less you can run with free rein, and past three minutes it pays to hold the effort back unless the session has a specific pace to learn. Do not run every rep all out: finish the session at a 6 or 7 out of 10, still able to do another rep, because going well beyond VO₂max builds work that does not drive a 5K or longer and makes you a little less efficient.

Treat it as one of your one or two hard sessions a week and not an extra. For a 5K, cluster this work in the last 6 to 8 weeks of the block, after at least 6 to 8 weeks of mostly easy running and threshold work first. See the guides on interval workouts, 5K and 10K training and strides.