VO2max: how to estimate it and improve it
VO2max is your aerobic ceiling: how much oxygen your body can use per minute and per kilogram. It is not everything, but it sets how much room you have.
VO2max — maximal oxygen uptake — is measured in millilitres of oxygen per minute per kilogram of body weight (ml/kg/min). It is the maximum amount of oxygen your body can take in, transport and use during maximal effort. In other words: the size of your aerobic engine.
It does not explain everything, but it sets the ceiling
Two runners with the same VO2max can finish a race minutes apart, because what decides a race is economy: how much oxygen you spend at a given pace. Even so, VO2max sets the upper limit. A low VO2max rarely sustains a fast marathon, and improving it is one of the most rewarding adaptations in training.
How to estimate it without a lab
An exercise test with gas analysis is the only exact method. For everyday use there are reliable estimates from a recent performance. Afterpacer uses Daniels' model: it computes the oxygen cost of the velocity you held and what percentage of your VO2max that effort represents, then divides. The table below is calculated with that formula, so the numbers are consistent with each other:
| 10K time trial | Pace (min/km) | Estimated VO2max | Equivalent 5K | Equivalent half | Equivalent marathon |
|---|---|---|---|---|---|
| 35:00 | 3:30 | 60.7 ml/kg/min | 16:47 | 1:17:13 | 2:41:00 |
| 40:00 | 4:00 | 51.9 ml/kg/min | 19:11 | 1:28:15 | 3:04:00 |
| 45:00 | 4:30 | 45.3 ml/kg/min | 21:35 | 1:39:17 | 3:27:01 |
| 50:00 | 5:00 | 40.0 ml/kg/min | 23:59 | 1:50:19 | 3:50:01 |
| 55:00 | 5:30 | 35.8 ml/kg/min | 26:23 | 2:01:21 | 4:13:01 |
| 1:00:00 | 6:00 | 32.3 ml/kg/min | 28:47 | 2:12:23 | 4:36:01 |
| 1:05:00 | 6:30 | 29.3 ml/kg/min | 31:11 | 2:23:25 | 4:59:01 |
| 1:10:00 | 7:00 | 26.8 ml/kg/min | 33:34 | 2:34:27 | 5:22:01 |
This shows the important part: the estimate is only as good as the recency and the effort of the mark. A hard 5K time trial counts; a comfortable 10K jog does not. And it is useful for tracking progress: the same mark in less time, or the same mark at a lower heart rate, means you have improved.
How to raise it
- Intervals at VO2max intensity. Sets of 3 to 5 minutes at a pace you could hold for roughly 6–12 minutes (not a sprint), with recoveries of equal or shorter duration. It is the most direct stimulus: it keeps oxygen consumption near maximum long enough.
- Aerobic volume in Z2. It sounds contradictory, but long easy work improves heart capacity and the capillary network, which is what sustains VO2max in the medium term. Without that base, intervals produce peaks that fade.
- Strength and hills. More force per stride and better economy: the same pace costs less oxygen, so your "effective" VO2max improves even if the number does not move.
- Weight. VO2max is per kilogram. Two extra kilos on a 70 kg runner is about 3 % of relative VO2max. With caveats: very low weight is not a goal, and certainly not at the cost of losing muscle.
A sensible plan is a 3 to 6 week block with one specific VO2max session per week, on top of base work. Improvements of 5–10 % are common in beginners; in someone who has trained for years, holding the value is already a result.
How Afterpacer uses it
Afterpacer estimates VO2max from your best efforts and charts it over time, so you see the trend rather than a single figure. It also feeds the race predictions, so if your real marks drift away from the prediction you have a clue: either the estimate or race day.
You can see the full coaching module in the demo with a real activity.
Frequently asked questions
What is a good VO2max?
It depends on age and sex, but roughly: below 40 ml/kg/min for men and 32 for women is low; 45–55 for men and 38–48 for women is a trained recreational level; above 60 for men and 52 for women is competitive territory. The absolute number matters less than how it evolves.
Can VO2max be improved at any age?
Yes, although the margin narrows with age and the absolute value tends to decline. The response to training remains: clear improvements are seen in 60-year-olds with aerobic work and well-dosed intervals.
How long does it take to improve?
Central adaptations (heart, blood volume) start within weeks, but a visible change in the estimate shows after 6 to 12 weeks of consistent work. The first months bring the largest gains.