Jack Daniels
and VDOT.

Who is Jack Daniels

Daniels won team medals in modern pentathlon at the 1956 and 1960 Olympics, then spent his career in exercise physiology and coaching, including long spells at SUNY Cortland and Northern Arizona. With Jimmy Gilbert he built tables that link race times to oxygen use, and from them came VDOT. Daniels' Running Formula first appeared in 1998 and is now in its fourth edition.

What VDOT is

VDOT is a number that describes your current running fitness, based on a recent race. It is not your measured VO2max. It is a "pseudo" VO2max that already includes your running economy. A 20:00 5K and a 41:40 10K give roughly the same VDOT, around 50. Once you have the number, the tables give you all your training paces.

The five Daniels paces

Pace	What it trains	How it feels
E, easy	Aerobic base, recovery, most of your volume	Conversational
M, marathon	Race-specific endurance	Steady, controlled
T, threshold	Lactate clearance, "comfortably hard"	About 1 hour race pace
I, interval	VO2max, in reps of 3 to 5 minutes	About 5K race pace or a bit faster
R, repetition	Speed and economy, short reps	Fast, with full recovery

Our training pace calculator gives you these zones from one race result, built on the same Daniels-style approach.

Daniels' rules that matter most

• Train at your current fitness, not your goal. Paces come from a recent race. Update them when you race faster, not before.
• Limit the hard stuff. Daniels caps quality: threshold running at about 10 percent of weekly volume, intervals at about 8 percent, repetitions at about 5 percent.
• Every run has a purpose. If you cannot say what a session trains, it is probably grey-zone running.
• Easy is most of it. Most of the week is E pace. Read why the easy run matters.

A Daniels-style week for a normal runner

Five runs: three easy, one threshold session (for example 3 x 8 minutes at T pace with 1 minute jog), one interval or long run with some M pace. That is the same backbone as our training week guide, and the sessions are in the interval library.

Sources: Jack Daniels, Daniels' Running Formula (4th edition, Human Kinetics, 2021), and his VDOT tables with Jimmy Gilbert. Paces in our calculator are estimates, not lab values.