VDOT — short for "V-dot-O2" — is Jack Daniels' proprietary running fitness score. Daniels designed it to produce a single number that predicts race times across any distance and dictates appropriate training paces. Once you have your VDOT, a lot of programming decisions become paint-by-numbers.

Why VDOT Is Useful

One race result predicts performance across all distances. Training paces scale automatically as you improve. Combines aerobic capacity and running economy into one number. Widely used by coaches and adopted by running communities worldwide.

The Five Training Intensities

Easy (E) — ~65-78% VDOT: The bulk of your mileage. Conversation pace. Builds aerobic base and aids recovery. Marathon (M) — ~80-85% VDOT: Used in marathon-specific training blocks. Threshold (T) — ~86-90% VDOT: Comfortably hard. Raises your lactate threshold. Interval (I) — ~95-100% VDOT: Hard. Develops VO2 max via 3-5 min intervals. Repetition (R) — ~105-120% VDOT: Fast, short bursts for speed and economy.

Getting the Best Result

Use a race where you gave full effort within the past 4-6 weeks, preferably in good conditions. Fueling, pacing mistakes, heat, and hills all depress your VDOT below your true fitness. If you race rarely, a hard 5K time trial works just as well.