By RunDoyen.
Featuring coaching insights from Sean Henning and Jacob Phillips.
RunDoyen connects runners with expert online running coaches and race-focused training plans built around real goals, real schedules, and long-term progress.
TL;DR
- Double threshold training means completing two threshold-focused workouts in one day, separated by several hours.
- Both sessions should stay controlled. The goal is not to complete two all-out workouts.
- A practical threshold effort feels comfortably hard and should be sustainable for roughly 20 to 30 minutes if run continuously.
- Double threshold can increase the amount of high-end aerobic work an experienced runner completes, but it also increases total training demand.
- Most runners with work, family, and limited recovery time do not need double threshold training to improve.
- Training history, workload tolerance, and recovery matter more than following a training method simply because it is popular.
If you want training decisions like this adapted to your current fitness, schedule, and race goals, Get Matched with a RunDoyen coach.
Table of Contents
- What is double threshold training?
- How hard should threshold running feel?
- Why do runners use two threshold sessions?
- Who should consider double threshold training?
- How to structure a double threshold day
- Common double threshold mistakes
- Safety and when to get help
- Is double threshold training necessary?
What Is Double Threshold Training?
Double threshold training is a training structure in which a runner completes two threshold-focused sessions in the same day.
The sessions are separated by several hours, giving the runner time to recover between the morning and evening workouts. Instead of putting all of the day’s quality work into one demanding session, the runner divides controlled aerobic work into two blocks.
That definition sounds simple, but the word threshold is where confusion begins.
Running terminology is not always consistent. Terms such as tempo, lactate threshold, aerobic threshold, and anaerobic threshold can mean different things depending on the coach or training system.
For this article, threshold means a high but controlled aerobic effort. The runner is working hard, but is trying to remain below the point where the session rapidly becomes much more difficult and fatigue begins escalating.
That distinction is also why understanding the difference between a tempo run and threshold run matters before adding a second quality session to the same day.
Double threshold is not simply “two hard workouts.”
It is two deliberately controlled workouts.
How Hard Should Threshold Running Feel?
One practical framework discussed by RunDoyen coach Sean Henning places threshold work at roughly 80 to 90 percent of VO2 max, depending on the athlete, workout, and purpose.
Most runners, however, are not testing VO2 max in a lab or measuring blood lactate during every workout. Effort therefore becomes especially important.
A threshold effort should feel comfortably hard. You might be able to exchange a few short phrases with a training partner, but you should not be carrying on an easy conversation.
Another useful check is duration. If you could not imagine sustaining the effort for approximately 20 to 30 minutes continuously, there is a good chance the workout has become too hard.
The legs provide another clue. A rapid increase in heaviness can signal that the athlete has moved beyond the intended intensity.
For runners interested in why different workout intensities create different training demands, RunDoyen’s guide to exercise physiology for runners provides useful context.
What About Blood Lactate Testing?
Advanced programs may use blood lactate measurements to make threshold work more precise.
Henning described roughly 2 to 4 millimoles per liter as a practical working range in this context, with readings moving above that range suggesting the athlete may be pushing beyond the intended threshold stimulus.
That kind of testing can add precision, but it is not required for most runners.
The bigger lesson is simpler: threshold training works best when the athlete resists the temptation to turn a controlled workout into a race.
That becomes even more important when another workout is coming later the same day.
Why Do Runners Use Two Threshold Sessions?
The appeal of double threshold is volume.
A hard VO2 max workout can create a large training stimulus, but it also creates substantial fatigue. Threshold training is typically more controlled, which can allow an experienced athlete to accumulate more quality aerobic work without making every session maximally demanding.
Splitting that work into two sessions can increase the total amount completed during the day.
One illustrative example is:
Morning: 5 x 2K at controlled threshold effort
Evening: 10 x 1 minute with 30 seconds of recovery at controlled threshold effort
The one-minute repetitions may be faster than the 2K repetitions because they are shorter, but that does not mean the evening workout should become a speed session.
That distinction is central to the entire method.
The potential benefit is not simply doing more. It is doing more of the right work at the intended intensity.
For runners whose goals span different racing distances, RunDoyen’s training plans reflect the broader principle that workout structure should match the athlete and event rather than follow one universal formula.
Who Should Consider Double Threshold Training?
Double threshold is most appropriate as an advanced training tool, not a default progression for every runner.
Henning began experimenting with the structure among a select group of experienced college athletes. Even within that group, not everyone did it.
That matters.
One athlete in his program earned All-American honors without completing a single double-threshold workout because the structure did not fit her previous training volume and overall load. Another highly successful athlete he coached never used double threshold either, with her longest threshold effort topping out at four miles.
The lesson is not that double threshold is ineffective. It is that good training does not require every useful training method to appear in every program.
Training maturity matters
Mileage alone does not determine readiness.
A runner needs enough training history to tolerate quality work predictably, recover between sessions, and understand what a controlled threshold effort actually feels like.
An athlete who routinely turns threshold sessions into races is not a good candidate for doubling them.
Schedule matters
Two workouts require two warm-ups, two sessions, two recovery windows, and more attention to fueling and logistics.
For a professional or college athlete, those demands may fit naturally into the day.
For someone balancing a full-time job, family responsibilities, and other commitments, forcing a second workout into late evening may create more problems than benefits.
The same practical principle appears in running while working full time: the best training structure is one that fits the athlete’s actual life well enough to be repeated consistently.
How to Structure a Double Threshold Day
For an athlete who is already prepared for this level of training, the following framework captures the coaching logic behind a double-threshold day.
- Define threshold before starting.
Know the intended effort. The purpose is controlled aerobic work, not two opportunities to test fitness. - Use the first session without emptying the tank.
Longer repetitions can work well in the morning because they encourage rhythm and restraint. - Allow several hours between sessions.
The sessions should be separated enough to create a meaningful recovery window rather than functioning as one enormous continuous workout. - Keep the second workout controlled too.
Shorter repetitions may naturally be quicker, but they should not turn into an unrelated high-intensity interval or repetition workout. - Judge the day by total stress, not one impressive split.
The value comes from accumulating quality work across both sessions. Chasing a fast time in one repetition can undermine the purpose of the entire day. - Consider cross-training when appropriate.
Some athletes may use a bike, elliptical, or another modality for the second session instead of adding another run. RunDoyen’s guide to cross training for runners explains how non-running aerobic work can fit into a broader program.
Henning’s college program used double threshold selectively, often around once every two weeks rather than multiple times every week, and moved away from it as the season progressed.
That is an important reminder that even for athletes who use the method, more is not automatically better.
Common Double Threshold Training Mistakes
- Assuming popular means necessary. A training method can be useful without being essential.
- Running the first session too hard. If the morning workout becomes a race, the evening workout is unlikely to remain productive.
- Turning the second session into speed work. Faster short repetitions can quickly drift beyond threshold intensity.
- Chasing splits instead of effort. A workout that looks impressive may no longer be accomplishing its intended purpose.
- Adding double threshold before building basic training consistency. Two quality sessions do not replace the need for a strong aerobic foundation.
- Ignoring the runner’s schedule. A theoretically good workout is not automatically good if it consistently disrupts sleep, family responsibilities, or recovery.
- Using the same structure for every athlete. Training background, event, workload tolerance, and recovery capacity all influence whether the method makes sense.
Safety and When to Get Help
General guidance: Double threshold increases the amount of demanding training completed in one day, so it should be approached conservatively.
If a runner develops pain, changes their running mechanics because of discomfort, or repeatedly struggles to recover from training, continuing to add intensity is unlikely to be the right response.
Persistent or concerning symptoms should be evaluated by an appropriate healthcare professional rather than self-diagnosed through a training plan.
From a coaching standpoint, repeated inability to keep threshold work controlled is also useful feedback. It may indicate that the athlete needs less total quality, more recovery, or a simpler training structure.
Is Double Threshold Training Necessary?
No single workout structure determines whether a runner will improve.
Double threshold can be a valuable way for a mature athlete to accumulate more high-quality aerobic work, but the method only works when the athlete can control the intensity and recover from the total load.
For many runners, one strong threshold session is the better choice.
A runner with a demanding job, family obligations, or limited training history may gain more from consistently completing one high-quality workout than from squeezing two threshold sessions into a day simply because advanced athletes use the method.
That principle applies far beyond double threshold training: adapt training to the athlete rather than forcing the athlete into the training method.
If you want one-to-one guidance on how threshold work and other key sessions should fit your training, Browse Coaches to learn more about RunDoyen’s online running coaches.
FAQ
What is double threshold training?
Double threshold training is a structure in which a runner completes two threshold-focused workouts in one day, usually with several hours of recovery between sessions. Both workouts are intended to remain controlled rather than becoming two maximal efforts.
How hard should a threshold workout feel?
A useful practical description is comfortably hard. You should be working noticeably harder than an easy run while retaining enough control to speak in short phrases. The effort should feel like something you could sustain for roughly 20 to 30 minutes continuously.
Do I need a blood lactate monitor for double threshold training?
No. Blood lactate testing can help advanced athletes quantify effort, but runners can also use perceived effort and other training feedback. The most important point is keeping the session controlled.
Is double threshold good for marathon runners?
It can be useful for some experienced runners because it increases the amount of aerobic quality work completed in a day. It is not required for marathon success, and schedule, training history, mileage tolerance, and recovery should determine whether it belongs in the program.
Can a low-mileage runner do double threshold training?
Possibly, but low mileage often reflects a reason the athlete is limiting running volume. Training maturity and workload tolerance matter more than simply reaching a specific weekly mileage number. For many lower-volume runners, another training structure will be more practical.
Can the second threshold workout be cross-training?
Yes. A threshold-style session on a bike, elliptical, or another aerobic modality can sometimes provide additional cardiovascular work without adding the same amount of running impact.
How much recovery should there be between threshold sessions?
There is no single required number of hours in the supplied coaching discussion. The key principle is to leave several hours between workouts so the athlete has a meaningful recovery period before the second session.
How can an online running coach help with double threshold training?
An online running coach can help determine whether the method fits the runner’s current training maturity, weekly workload, race goals, recovery capacity, and schedule. Coaching can also help prevent a controlled threshold day from becoming two unnecessarily hard workouts.
