Marathon Lactate Threshold Training: The Workout Type That Matters Most

Lactate threshold—the intensity where lactate accumulation accelerates—is among the most important physiological determinants of race performance. Understanding threshold training and incorporating it appropriately improves racing capability more than almost any other single training focus.
Lactate threshold occurs at approximately the pace you could sustain for about one hour of maximum effort. At intensities below threshold, your body clears lactate as fast as it produces it, allowing sustainable effort. Above threshold, lactate accumulates faster than clearance, leading to rapid fatigue. Improving your threshold—either the pace at which it occurs or your ability to sustain work above it—directly translates to improved race performance.
Tempo runs are classic threshold training—sustained efforts of 20-40 minutes at comfortably hard pace, typically described as “controlled discomfort.” You’re working hard but not all-out, breathing heavily but able to speak in short phrases, sustainable for the workout duration but relieved when it ends. This intensity specifically targets threshold adaptation, training your body to clear lactate more efficiently and tolerate sustained hard effort.
Cruise intervals break threshold work into segments with short recovery—perhaps 3-4 x 10-12 minutes at threshold pace with 1-2 minute recovery jogs between. This format allows accumulation of time at threshold intensity when continuous tempo runs of that total duration would be too hard. The brief recoveries provide mental breaks making the total work more tolerable while still stressing threshold systems.
Threshold training frequency depends on training phase and runner experience. During base building, threshold work might happen once weekly or less. During race-specific phases, perhaps twice weekly including one tempo run and one interval session at similar intensity. More than two threshold sessions weekly for recreational runners risks inadequate recovery and accumulated fatigue. Quality of threshold work matters more than quantity—one well-executed threshold session provides better adaptation than three mediocre sessions run too fast or too slow.
The pace for threshold training is moderate-hard, not all-out. Common mistakes include running threshold workouts too fast, treating them like races rather than controlled efforts. If you’re completely exhausted and unable to maintain pace for the prescribed duration, you started too fast. Threshold work should feel sustainable—challenging but controlled. Using heart rate or perceived effort rather than rigid pace targets helps ensure you’re working at appropriate intensity regardless of conditions affecting pace.
Progression in threshold training comes from extending duration, increasing pace slightly over training cycle, or shortening recovery intervals in cruise interval format. This progressive challenge forces continued adaptation rather than simply maintaining current threshold. However, progression should be gradual—don’t try to extend threshold runs from 20 minutes to 40 minutes in one jump. Adding 5 minutes every 2-3 weeks allows adaptation to increasing demands.
Threshold training benefits translate most directly to race performance because races are typically run near threshold intensity. The better your threshold, the faster pace you can sustain for race duration. This makes threshold work crucial for runners targeting improved race times. However, threshold training is demanding and requires recovery—it should be balanced with easy running that supports overall training volume and with occasional higher-intensity interval work that stresses different energy systems. The runners who excel at racing are usually those with well-developed lactate thresholds built through consistent threshold training over months and years. This physiological adaptation can’t be rushed—it develops gradually through repeated exposure to threshold intensity with adequate recovery allowing adaptation to occur. But for runners willing to put in consistent threshold work over time, the performance improvements are substantial and directly relevant to their race goals in ways that some other training types aren’t.