What VDOT is
VDOT is a running fitness index developed by coach Jack Daniels. It comes from two equations fitted to lab data: one for the oxygen cost of running at a given speed and one for the share of VO2max a runner can hold for a given race duration. A recent race result therefore gives a single number that sets training paces and predicts other distances.
The formulas
With speed v in meters per minute and race time t in minutes:
- Oxygen cost: VO2 = −4.60 + 0.182258 v + 0.000104 v²
- Share of VO2max sustained: %max = 0.8 + 0.1894393 e^(−0.012778 t) + 0.2989558 e^(−0.1932605 t)
- VDOT = VO2 ÷ %max
Examples
| Race | Time | VDOT |
|---|---|---|
| 5K | 25:00 | 38.3 |
| 10K | 50:00 | 40.0 |
| 5K | 20:00 | 49.8 |
| Half marathon | 1:45:00 | 42.6 |
| Marathon | 3:30:00 | 44.6 |
A 25:00 5K means an average of 8:03 per mile while holding about 94% of VO2max.
Training paces
The calculator converts fixed shares of VDOT back into speeds:
- Easy (about 70%): conversational runs, most of the weekly mileage.
- Threshold (about 88%): “comfortably hard” tempo runs of 20 minutes or cruise intervals.
- Interval (about 98%): 3 to 5 minute repeats that build VO2max.
For a VDOT of 38.3 these are about 10:11, 8:29 and 7:47 per mile. Daniels’ published tables use ranges, so treat these as central values.
Using VDOT well
- Use a recent, all-out race on a flat course. Hot weather, hills or a poor day lower the result.
- VDOT differs from a lab VO2max: it also reflects running economy.
- Raise your training paces only after a new race or several weeks of strong workouts, by about one VDOT point at a time.
- Very short races favor fast-twitch runners and very long ones favor endurance; a VDOT from the 5K to half marathon range predicts best.