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AnswersWhat is VDOT?
VDOT is a single number for running fitness, developed by the coach and physiologist Jack Daniels. It is worked out from a recent race time and behaves like an effective VO₂max: the same number predicts what you can run at other distances and sets every training pace, from easy runs to intervals. A 20-minute 5 km is roughly VDOT 50.
VDOT from a 5 km, and what it predicts
| 5 km | VDOT | 10 km | Half | Marathon |
|---|---|---|---|---|
| 35:00 | 25.6 | 1:12:53 | 2:40:58 | 5:28:30 |
| 30:00 | 30.8 | 1:02:23 | 2:18:09 | 4:43:39 |
| 27:00 | 35.0 | 56:05 | 2:04:19 | 4:16:19 |
| 25:00 | 38.3 | 51:53 | 1:55:03 | 3:57:55 |
| 22:00 | 44.5 | 45:37 | 1:41:07 | 3:30:03 |
| 20:00 | 49.8 | 41:28 | 1:31:50 | 3:11:17 |
| 18:00 | 56.3 | 37:20 | 1:22:33 | 2:52:25 |
Two parts make it work. One describes how much oxygen running at a given speed costs; the other describes what fraction of your maximum you can sustain for a given length of time. Put a race result through both and out comes a number that is not quite VO₂max — it folds in running economy — but that predicts performance far better than a lab test does.
Where it is weakest
Predictions stretch less well the further they reach. A 5 km result predicts a 10 km closely and a marathon loosely, because the marathon also depends on endurance, fuelling and pacing that a 5 km does not test. Beyond the marathon the model is not built for it at all, which is why Race Shape does not publish ultra goal times from it.
Common questions
Is VDOT the same as VO₂max?
No. It behaves like one, but it is derived from a race rather than measured in a lab, so it includes how economically you run. Two runners with the same lab VO₂max can have quite different VDOTs.
How often should I update it?
After any race or time trial that was a genuine effort, and at least every six to eight weeks in a training block. Paces set from a number that is months old are paces for somebody you no longer are.
What race is best for working it out?
A recent 5 km or 10 km run hard, on a flat course, in reasonable weather. Those give the cleanest number.
Sources
- Daniels, J. & Gilbert, J. (1979). Oxygen Power: Performance Tables for Distance Runners.
- Daniels, J. Daniels' Running Formula.