VDOT & Training Paces Calculator

Jack Daniels’ VDOT system is one of the most widely respected training frameworks in modern running. Popularized in his book Daniels’ Running Formula, VDOT represents your “effective VO2 Max”—a single value that accounts for both your cardiovascular capacity and your running economy (how efficiently your body uses oxygen at a given speed).

By entering a recent race result in the calculator above, you can determine your exact VDOT score and find the corresponding training paces for your Easy (E), Marathon (M), Threshold (T), Interval (I), and Repetition (R) training sessions.

Once calculated, you can enter these paces manually in the Apex Run App under Settings → Training Pace Zone to evaluate your workouts using your personal training zones.

The Five Training Paces (E-M-T-I-R)

#

Daniels’ system defines five specific training zones, each designed to stimulate a distinct physiological adaptation.

1. Easy Pace (E)

#

• Intensity: ~58% to 72% of VDOT (conversational effort).
• Purpose: Builds your aerobic foundation, strengthens muscles and tendons, increases vascularization, and promotes active recovery.
• Application: Warmups, cool-downs, recovery runs, and weekly long runs. Most of your weekly mileage should be run at Easy pace.

2. Marathon Pace (M)

#

• Intensity: ~79% to 83% of VDOT.
• Purpose: Develops cardiovascular endurance and builds psychological confidence for running long distances at race pace.
• Application: Long steady-state runs or race-pace simulations during marathon training.

3. Threshold Pace (T)

#

• Intensity: ~85% to 89% of VDOT (comfortably hard effort).
• Purpose: Raises your lactate threshold—the point at which your body produces more lactate than it can clear. Training at this pace teaches your body to clear lactate efficiently, allowing you to sustain a fast pace for longer.
• Application: Tempo runs (20-30 minutes continuous) or cruise intervals (e.g. 5-6 × 1 mile reps with 1 minute rest).

4. Interval Pace (I)

#

• Intensity: ~95% to 100% of VDOT (hard effort, roughly 5K race pace).
• Purpose: Directly targets and expands your aerobic capacity (VO2 Max)—the absolute ceiling of your oxygen processing system.
• Application: High-intensity intervals (e.g., 800m or 1000m repeats on the track) with recovery jogs equal to or slightly shorter than the run duration.

5. Repetition Pace (R)

#

• Intensity: ~102% to 105% of VDOT (very fast, anaerobic speed).
• Purpose: Improves running economy, neuromuscular coordination, and speed. The goal is to make running at all other paces feel lighter and more efficient.
• Application: Short, fast repetitions (e.g., 200m or 400m repeats) with full recovery between reps to ensure proper mechanics.

Why You Should Avoid the “Grey Zones”

#

In Daniels’ system, the zones are distinct because they target specific physiological adaptations. Running in the gaps between these zones (e.g., faster than Easy pace but slower than Marathon pace) is known as training in the Grey Zones.

Grey zone training compiles high cardiovascular fatigue without providing the full stimulus of either adjacent zone. It is a common training mistake for runners to run their Easy runs too fast and their Hard runs too slow. For optimal progression, keep your Easy runs truly easy and your Hard runs precisely targeted.

Training Analysis in Apex Run

#

In the Apex Run App, you do not need to manually enter each calculated training pace:

1. Navigate to Settings → Calculate Pace Zones.
2. Choose your recent Benchmark Run distance and enter your finish time.
3. The App will automatically determine your VDOT score and configure your 5 training pace zones.

Once set up, Apex Run dynamically evaluates your workouts. In the Run Detail screen of every run, you will find a precise breakdown showing exactly how much time you spent in each pace zone (such as Below Easy, Easy Pace (E), Easy - Marathon, Marathon Pace (M), Threshold Pace (T), Interval Pace (I), and Repetition Pace (R)). This allows you to immediately see if you executed your session targets correctly or drifted into the unproductive grey zones.