Jack Daniels' training paces: what E, M, T, I and R train and how much to run

Jack Daniels organizes running training into five intensities, each with one job. E (easy) builds the base and M (marathon) rehearses the race. T (threshold) improves lactate clearance, I (interval) stresses VO2max and R (repetition) trains speed and running economy. All five paces come from a single measurement, the fitness score that Daniels' tables assign to a recent race, so they stay in proportion to each other (Daniels, Daniels' Running Formula, 4th ed., ch. 5). Once you know what each pace is for, you know when to push, when to hold back and how much of each to run in a session.

This guide explains what each letter trains and where it sits as a percentage of VO2max and maximum heart rate according to Daniels himself. It also covers the format and dose of each session and the mistakes that most often wreck the method. At the end you see how a Daniels plan from our catalog spreads the five intensities over a week, and how to get your own paces from a recent race with the Magic pace calculator.

Key takeaways

• E (59 to 74% of VO2max), M (75 to 84%), T (83 to 88%), I (95 to 100%) and R (speed, not tied to VO2max) are Daniels' five intensities. Each trains a different component, and all five paces come from the same recent race.
• Per-session dose is part of the method: T up to 10% of weekly mileage, I up to 8% (10 km / 6 miles max), R up to 5% (8 km / 5 miles max), M up to 110 minutes or 29 km (18 miles), long run up to 25 to 30% of the week.
• I reps last 3 to 5 minutes because the body takes about 2 minutes to reach VO2max; R reps stay under 2 minutes, with 2 to 3 times the work time as recovery.
• The costliest mistakes: running easy days at a moderate effort, setting paces from a goal instead of a recent race, and running I faster "because you can". In one study of very short 15-second reps, running them at 110% of VO2max speed produced half the time at VO2max.
• Within the week, Daniels alternates quality (Q) sessions with E days; the marathon program has two Q sessions per week, and everything else is truly easy.

Where the five paces come from

Daniels starts from a recent race, not a goal. The time from a race you actually ran becomes a fitness score in the book's tables, and each score has a fixed set of E, M, T, I and R paces (Daniels, Daniels' Running Formula, 4th ed., ch. 5). The Magic pace calculator makes the same conversion: you enter the race distance and time, and it returns your Magic Index, the calculator's version of Daniels' fitness score, and the five paces. Any race from the last two or three months, from 5K to the marathon, will do. The closer it is to your target distance, the better the estimate.

The table below sums up what each pace trains, the physiological range Daniels gives it in the chapter on training types and intensities, and the race you could hold it for. The VO2max and HRmax ranges are from the book, and so are the race equivalents. Treat heart rate as a reference, not a target: the same percentage of HRmax lands in different zones for different runners (Nuuttila et al., 2025).

E pace: the base for everything

E pace is where most of the miles in any Daniels plan live. At 59 to 74% of VO2max (65 to 79% of HRmax), it is comfortable enough to talk and slow enough to repeat the next day (Daniels, 2022, ch. 4). Daniels credits this intensity with developing the heart muscle, the capillary network and the muscle cells that use oxygen, plus resistance to injury from volume accumulated with little metabolic cost.

Elite practice agrees on the proportion. In world-class distance runners, at least 80% of running volume is low intensity throughout the year (Haugen et al., 2022). Their easy runs are about 3 to 5 km/h (roughly 2 to 3 mph) slower than marathon pace. The full logic of that distribution is in 80/20 polarized training.

Dose for E pace

E covers warm-ups, cool-downs, recovery days between quality sessions and the long run. In the book, Daniels caps the long run at the lesser of 25% of weekly mileage and 150 minutes for runners above 64 km (40 miles) per week; below that, 30% of the week (Daniels, 2022, ch. 4).

For a runner at 60 km (37 miles) per week, that is an 18 km (11-mile) long run, close to 1h45 at E pace. The rest of the marathon long run is covered in the long run.

In elite runners, easy runs last 40 to 70 minutes (Haugen et al., 2022). Daniels suggests adding short, relaxed strides at the end of a couple of E days each week (Human Kinetics, excerpt from Daniels' program). The recovery pace the calculator shows separately is the slow edge of the E range.

When easy drifts into moderate

This is the most common mistake and the most expensive one. In 165 recreational runners, the first lactate threshold sat on average at 80.7 ± 4.9% of HRmax (Nuuttila et al., 2025). Run your E days at 85% and you are past the first threshold, in the zone Daniels reserves for M. In highly trained runners, heart rate variability returned to baseline within 5 to 10 minutes after 60 or 120 minutes below the first ventilatory threshold. After 30 minutes between the thresholds it took about 30 minutes, the same as after an interval session (Seiler, Haugen and Kuffel, 2007). In autonomic terms, the moderate run cost the recovery of an interval session without delivering its stimulus.

M pace: the race rehearsal

M pace is the pace you intend to run the marathon at, between 75 and 84% of VO2max (80 to 90% of HRmax) (Daniels, 2022, ch. 4). Physiologically it sits close to a long E run; the difference is the purpose. Daniels uses M so the runner gets used to race pace, learns to drink and eat at it and builds confidence that it holds up when tired. In more than 25,000 recreational marathoners, the marathon was run on average at 84.8% of critical speed, with the fastest at 93% (Smyth and Muniz-Pumares, 2020). M therefore sits well below threshold, and it should feel sustainable when it starts.

Dose for M pace

M shows up as a continuous run or as blocks inside the long run: 8 km easy, 13 km at M, 9 km easy, for example (5 + 8 + 5.6 miles). In the book, a single M session is capped at the lesser of 110 minutes and 29 km (18 miles) (Daniels, 2022, ch. 4).

For a 3:30 marathoner, 29 km at M takes almost 2h25, so the practical ceiling is the 110 minutes, about 22 km (13.7 miles). Half marathoners can use M as a steady endurance run, but the specific pace for the half is T. The structure of the race-specific phase is in training for a marathon.

T pace: "comfortably hard"

T pace is the lactate threshold in Daniels' definition: the highest intensity at which lactate production and clearance still balance. In the book it sits between 83 and 88% of VO2max (88 to 92% of HRmax), closer to 86 to 88% in well-trained runners, and matches the pace a rested runner could race for about 60 minutes (Daniels, 2022, ch. 4). In practice, for most amateurs it falls between 10K and half marathon pace; for someone who runs the half in about an hour, it is practically half marathon pace.

The goal of T is to teach the body to clear lactate as fast as it produces it and, with that, push the threshold upward. It is the most specific workout for the half marathon, and the dose decides the result. In a 9-week trial, the group that did 54% of its training between the thresholds showed no significant improvement in any performance variable (Stöggl and Sperlich, 2014). The full analysis is in threshold training for the half marathon.

Dose for T pace

Daniels uses two formats. The tempo run is a continuous run of about 20 minutes at T. Cruise intervals are reps of 3 to 15 minutes at T with short rests, about 1 minute per 5 minutes of work. Examples: 5 × 1 mile with 1 minute, 3 × 2 miles with 2 minutes, or 4 × 10 minutes with 90 seconds. In either format, the T work in one session does not exceed 10% of weekly mileage (Daniels, 2022, ch. 4).

At 60 km (37 miles) a week, that is 6 km (3.7 miles) at T, or 5 × 1,200 m; at 100 km (62 miles), 10 km (6.2 miles), or roughly 2 × 20 minutes.

If the session ends feeling like a 10K race, the pace was above T and the workout changed zones. The right sign: in the last reps you could still do one more without forcing your breathing.

I pace: the VO2max workout

I pace is the intensity that drives oxygen consumption to its maximum: 95 to 100% of VO2max, 98 to 100% of HRmax (Daniels, 2022, ch. 4). In a race, it is the pace you could hold for 10 to 15 minutes, close to 3K to 5K for an amateur. Daniels prescribes I to raise VO2max, and the literature points the same way for trained runners. The review by Midgley, McNaughton and Wilkinson (2006) concludes that training at or near VO2max is probably the most effective intensity for improving it in well-trained runners. The role of VO2max in performance is in VO2max for runners.

Dose for I pace

The rep length comes from physiology. Daniels notes that the body takes about 2 minutes to reach VO2max from rest, so each rep has to last long enough to spend time there. Three to 5 minutes is ideal, and shorter reps only work if the recoveries are also short (Daniels, 2022, ch. 4). The review by Buchheit and Laursen (2013) proposes the same criterion: the optimal stimulus includes several minutes per session above 90% of VO2max. For a runner with an I pace of 4:16/km (6:52/mi), 3 to 5 minutes is 800 to 1,200 m.

The recovery is a jog equal to or slightly shorter than the work time, so oxygen consumption does not fall back to baseline and the next rep climbs faster. The per-session dose is the lesser of 8% of weekly mileage and 10 km (6 miles) at I (Daniels, 2022, ch. 4).

At 60 km (37 miles) a week, that is 4.8 km (3 miles): 6 × 800 m or 4 × 1,200 m. Formats and progressions are in interval training for runners.

Why not to run I faster

Faster than I is not more VO2max; it is a different workout. In a study of middle-aged runners doing very short 15-second reps, running at 110% of VO2max speed yielded about 7 minutes at VO2max (Billat et al., 2001). The protocols at 90 to 100% yielded 14 minutes, with lower lactate at the end: 9 versus 11 mmol/L. The study used short reps, not Daniels' 3-to-5-minute ones, but it points the same way as the method's rule. If you finish the first reps with room to spare and speed up, the last ones get cut short or the recoveries stretch, and the accumulated time at VO2max drops. The pace from the table is the target; feeling like you "could do more" in the first reps is part of the design.

R pace: speed and economy

R pace is the fastest of the five and the only one Daniels does not define by a percentage of VO2max. It sits close to 1,500 m or mile race pace, above the speed at VO2max (Daniels, 2022, ch. 4). The goal is mechanical and neuromuscular: run fast with good form, without piling up fatigue, to improve speed and running economy. Running economy is the oxygen cost of holding a given speed, a concept Daniels himself helped formalize (Daniels, 1985).

Dose for R pace

R reps stay under 2 minutes: 200, 300 and 400 m are the classic formats, with 600 m for fast runners. The recovery is long, 2 to 3 times the work time, because the point is for every rep to come out fast and relaxed, not tired. The book's example is 10 × 400 m with 3 minutes of recovery. The per-session dose is the lesser of 5% of weekly mileage and 8 km (5 miles) (Daniels, 2022, ch. 4). At 60 km (37 miles) a week, that is 3 km (1.9 miles): 10 × 300 m, or 7 × 400 m. Strides at the end of easy runs are the minimum version of this work and fit any phase.

Dose per session: the reference table

The table gathers the dose rules Daniels gives in the book and applies each one to two common weekly volumes. The limits are per session, not per week, and they count only the work at the intensity, not warm-up, recoveries or cool-down.

The examples are arithmetic on the book's rules, not prescribed workouts. In the specific phase, a long session with an M block is a quality session with its own ceiling, and the catalog plan shown below uses sessions like that which run longer than the easy long run. The 20 km long run at 80 km a week respects the 25% ceiling, but a runner at 7:30/km (12:04/mi) would need 150 minutes to cover it and hits the 150-minute ceiling as well.

How to build the week

Daniels' assembly rule is simple: quality (Q) sessions in order, with E days between them. In the book's program for 5K to half marathon, there are up to three Q sessions per week, Q1, Q2 and Q3 (Human Kinetics, excerpt from Daniels' program). E days sit between them, with strides on two of the easy days. For the marathon, the book's 2Q program uses two quality sessions per week, and the rest of the week is E. The intensities come in by phase: first only E with strides, then R, then I, and last T and M, the most specific ones for a long race (Daniels, 2022, ch. 4).

Elite runners build the week the same way. Highly trained and elite runners use continuous threshold runs and interval sessions at least once a week each, in a pyramidal distribution that turns polarized near competition (Casado et al., 2022). Threshold-zone work makes up 5 to 15% of volume and intervals above it another 5 to 15%; one rises as the other falls (Haugen et al., 2022). How Daniels compares with other marathon methods is in Daniels vs Pfitzinger vs Hansons.

A real week from a Daniels plan in the catalog

The table shows weeks 15 to 17 of the intermediate Daniels marathon plan in the Magic Training catalog, 24 weeks long with six runs per week (catalog data read on 2 Nov 2026). The plan spends weeks 1 to 6 entirely at E, with the long run growing from 85 to 135 minutes. It brings in I and T in week 7 and places M blocks inside the long run from week 15 on. There is a simulated half marathon in week 20 and the race in week 24.

The 19 km (12 miles) at M in week 17 take about 94 minutes for a runner at 4:57/km (7:58/mi), inside the 110-minute ceiling. The two Q sessions are separated by three E days, and the whole week has a single I or T workout. In week 15, each 1,600 m takes about 6:50 for a runner with I at 4:16/km (6:52/mi), above the 3-to-5-minute range; if the last reps lose pace, 1,200 m does the same job. In T weeks, the plan uses both cruise intervals (4 × 10 minutes with 90 seconds, in week 12) and the continuous 35 minutes of week 16.

Common mistakes

Two mistakes already came up above: easy runs that drift into moderate, in the E pace section, and I reps run faster than the table, in the I pace section. Three more break the method just as often.

Setting paces from the goal, not from a recent race

A T pace calculated from the time you want to run shifts the whole week upward: every rep becomes a piece of a race, and the easy volume stops being easy. Daniels takes the score from a race you ran, and the paces track your current fitness (Daniels, 2022, ch. 4). The goal gets tested on race day. Redo the calculation after every 10K or half you race for real; the intermediate plan in the catalog asks for that update in week 12.

Adding threshold to easy days

When easy runs drift into moderate, the volume between the thresholds climbs week after week, and that is the profile that did not improve in the 9-week trial cited in the T pace section. Threshold works inside the 10% per-session budget, with the rest of the week at E.

Forgetting to update the paces

The paces are valid for the fitness the race measured. After 6 to 8 weeks of consistent training, or after a new race, the score changes and so do the tables. Training for months on old paces underestimates the stimulus; training on a hot day with paces from a race run in ideal conditions overestimates it. In both cases, the reference is the most recent comparable race.

How to get your paces from the Magic pace calculator

Take the most recent race you actually ran, ideally from the last two or three months, and enter the distance and time in the Magic pace calculator. It returns your Magic Index, the recovery, E, M, T, I and R paces, and equivalent times at other distances.

For a 10K in 45:00 (4:30/km, 7:14/mi), the calculator gives E at 5:23 to 6:03/km (8:40 to 9:44/mi), M at 4:57/km (7:58/mi) and T at 4:38/km (7:27/mi), checked on 2 Nov 2026. I comes out at 4:16/km (6:52/mi, or 1:42 per 400 m) and R at 94 seconds per 400 m, about 3:55/km (6:18/mi).

The numbers match the method's relationships: T is 8 seconds per kilometer slower than 10K pace, I is 14 seconds faster and M is 27 seconds slower. If your Garmin estimates a different threshold, treat the estimate as an alarm and the race as the reference. How pace, heart rate and effort translate into each other is covered in running training zones.

With the paces in hand, the next step is a plan that uses them. In the Daniels plans in our catalog, every workout comes with the right zone and goes to your watch through Garmin workout sync, with no reps to memorize. After each new race, enter the time in the plan's pace settings so the workouts follow your current fitness.

Frequently asked questions

What is the difference between T pace and Garmin's lactate threshold?

Daniels' T is the pace of a roughly 60-minute race, derived from the tables using a recent race. The watch estimates the threshold from its VO2max estimate, heart rate and pace during hard runs, and a 2025 systematic review of wearables found that their lactate threshold estimates are not yet accurate enough to replace a test (Železnik Mežan, 2025). Use the watch as a reference and the race as the target.

Do I need all five paces every week?

No. Daniels spreads the intensities across phases: only E at the start, then R, then I, and T and M in the specific phase (Daniels, 2022, ch. 4). In the intermediate marathon plan in the catalog, a typical week has two quality sessions, one at I or T and a long run with an M block, and everything else at E. Strides at the end of easy runs keep a touch of R all year.

Is I pace the same as 5K pace?

Close, but not the same. Daniels defines I as the pace of a 10- to 15-minute race, which is 3K to 5K depending on your level. For the 45-minute 10K runner, the calculator gives an I pace of 4:16/km (6:52/mi) and an equivalent 5K of 21:50, or 4:22/km (7:02/mi). For someone who runs 5K in under 15 minutes, I sits closer to 3K pace.

Can I swap the easy long run for a long run at M pace?

Partly. Daniels places M blocks inside the long run in the specific phase, like the 13 km (8 miles) at M inside 30 km (18.6 miles) in week 15 of the catalog plan. The per-session ceiling is the lesser of 110 minutes and 29 km (18 miles) at M (Daniels, 2022, ch. 4), and the rest of the long run stays at E. A full long run at M every week becomes a weekly race and charges the recovery of one.

How many easy days after a race in the middle of the plan?

Daniels' rule is one E day for every 3 km of race distance: five days after a 15K, seven after a half marathon (Human Kinetics, excerpt from Daniels' program). Only then do the Q sessions return. Use the race to update your paces in the calculator before resuming.

References

• Daniels J. Daniels' Running Formula. Champaign: Human Kinetics, 4th ed., 2022. Chapter 4, "Types of Training and Intensities", and chapter 5 on the pace tables. Publisher's page
• Human Kinetics. Sample running program from Daniels' Running Formula (excerpt from the 4th ed.: Q1, Q2 and Q3 sessions with E days between them; one E day per 3 km of race). humankinetics.com
• Daniels JT. A physiologist's view of running economy. Medicine and Science in Sports and Exercise, 1985;17(3):332-8. PubMed 3894870
• Midgley AW, McNaughton LR, Wilkinson M. Is there an optimal training intensity for enhancing the maximal oxygen uptake of distance runners? Sports Medicine, 2006;36(2):117-32. PubMed 16464121
• Buchheit M, Laursen PB. High-intensity interval training, solutions to the programming puzzle. Part I: cardiopulmonary emphasis. Sports Medicine, 2013;43(5):313-38. PubMed 23539308
• Billat VL, Slawinski J, Bocquet V, Chassaing P, Demarle A, Koralsztein JP. Very short (15s-15s) interval-training around the critical velocity allows middle-aged runners to maintain VO2max for 14 minutes. International Journal of Sports Medicine, 2001;22(3):201-8. PubMed 11354523
• Seiler S, Haugen O, Kuffel E. Autonomic recovery after exercise in trained athletes: intensity and duration effects. Medicine & Science in Sports & Exercise, 2007;39(8):1366-73. PubMed 17762370
• Nuuttila OP, Kaikkonen P, Sievänen H, Vasankari T, Kyröläinen H. The accuracy of fixed intensity anchors to estimate lactate thresholds in recreational runners. European Journal of Applied Physiology, 2025;125(8):2161-71. PMC12354492
• Haugen T, Sandbakk Ø, Seiler S, Tønnessen E. The training characteristics of world-class distance runners: an integration of scientific literature and results-proven practice. Sports Medicine - Open, 2022;8(1):46. PMC8975965
• Smyth B, Muniz-Pumares D. Calculation of critical speed from raw training data in recreational marathon runners. Medicine & Science in Sports & Exercise, 2020;52(12):2637-45. PMC7664951
• Železnik Mežan L. Accuracy of wearables for determining the maximal oxygen uptake and lactate threshold: a qualitative systematic review. Frontiers in Sports and Active Living, 2025. PMC12748164
• Stöggl T, Sperlich B. Polarized training has greater impact on key endurance variables than threshold, high intensity, or high volume training. Frontiers in Physiology, 2014;5:33. Frontiers
• Casado A, González-Mohíno F, González-Ravé JM, Foster C. Training periodization, methods, intensity distribution, and volume in highly trained and elite distance runners: a systematic review. International Journal of Sports Physiology and Performance, 2022;17(6):820-33. PubMed 35418513
• Catalog data read on 2 Nov 2026 from the workouts of the intermediate Daniels marathon plan (24 weeks), week by week, with the zone marked on each session.
• Magic pace calculator, Magic Training, checked on 2 Nov 2026 for a 10K in 45:00. magic.training/en/calculadora