How to Boost Your Lactate Threshold

Lactate threshold development requires building a base, then progressively increasing intensity through submaximal efforts, split sessions, alternations, and aerobic intervals. The lactate curve reflects a balance between aerobic and anaerobic systems, not just aerobic capacity.

Lactate threshold (the pace at which lactate production equals removal) is often misunderstood. It’s not purely aerobic; it reflects a balance between aerobic efficiency and anaerobic capacity. Training threshold requires a specific progression and understanding of the lactate curve.

The Science Simplified

Lactate is not the enemy. It’s a fuel and signaling molecule. The confusion: hydrogen ions (not lactate) accumulate alongside lactate and contribute to fatigue. Modern understanding: lactate production triggers beneficial adaptations.

The lactate curve:
– Relatively flat at low intensities (zone 1-2)
– Begins rising at aerobic threshold (~2 mmol/L)
– Rises faster approaching lactate threshold (~3-4 mmol/L depending on the athlete)
– Steep rise above threshold (anaerobic zone)

Shifting the curve right (higher lactate threshold at the same pace) = aerobic improvement. But the curve can also shift due to anaerobic changes, which complicates interpretation.

The Aerobic-Anaerobic Balance

Your lactate curve reflects a push-pull between two systems:

Aerobic system pulls the curve right: Better aerobic capacity = you can go faster at lower lactate levels.

Anaerobic system pulls the curve left: Better anaerobic system (more fast-twitch fibers, more lactate production) = higher lactate at any given speed.

The trap: If you do only long slow distance, you improve aerobically (curve shifts right). But kill your anaerobic system with no speed work, and you might have high lactate at race pace because you’ve lost fast-twitch capacity. You think you’ve detrained, but you’ve actually become “aerobically strong but anaerobically weak.”

The solution: Balance is essential. Need some speed maintenance year-round.

Prerequisites: Build Your Base First

You cannot develop threshold effectively without an aerobic foundation. The infrastructure (capillaries, mitochondria, oxidative enzymes) allows threshold work to generate adaptations.

Foundation: Lots of easy volume (zone 1-2), perhaps 8-12 weeks. How much depends on experience level:
– Novice: 20-50 miles/week of easy running
– Intermediate: 50+ miles/week
– Advanced: Can blend base with some intensity

Without foundation, threshold work just builds fatigue without optimal adaptation.

Step 1: High-End Aerobic Work (“Connector”)

After base building, introduce high-end aerobic work before dedicated threshold training. This bridges the gap between easy runs and threshold intensity.

What it is: Marathon pace, steady runs, or progressions that start easy and finish faster.

Examples:
– 8-12 miles with last 3-4 miles at marathon pace
– 10 mile progression: easy → steady → marathon pace at finish
– Tempo-like effort but not threshold

Purpose: Recruit slightly harder-to-activate slow-twitch fibers and prepare for threshold work ahead.

Step 2: Below to Just-Below Lactate Threshold

This is the core threshold development work. Train at 2-3 mmol lactate (just below the point where lactate starts rising steeply).

Why below rather than at threshold?
– Easier to manage psychologically (not on the edge)
– Allows more total volume at threshold intensity
– Less risk of overtraining at the edge
– Talk test: You should be able to speak a sentence or two, but conversation is hard

Format: Split threshold sessions (more effective than one long effort)

Instead of 25-30 minutes continuous at threshold, do:
– 5 x 5 minutes with 45-second to 1-minute easy jog recovery
– Or: “Dealer’s choice”—athlete decides when to take small breaks while maintaining total time
– Example: 35 minutes total at threshold pace, broken up however the athlete needs

Why splits work:
– Physiologically: Similar lactate stimulus with less continuous discomfort
– Mentally: Breaking up the effort makes it psychologically easier
– Practically: You accumulate more total time because mental fatigue decreases

Step 3: Threshold Plus (Add Components)

Once comfortable with baseline threshold, add variations to increase stimulus:

Progression at the end:
– 6 x 5 min at lactate threshold, with the last one pushed faster (3k pace)
– Builds speed into sustained effort

Hill incorporation:
– Threshold run with a portion uphill
– Changes muscle recruitment and adds strength component
– Slightly slower pace but same lactate stimulus due to hills

Purpose: Trigger additional adaptations without drastically increasing lactate accumulation.

Step 4: Alternations (Above and Below Threshold)

Play above and below threshold in alternating intervals.

Example structure:
– 5 cycles of: 400m at 10k pace + 1200m at marathon pace (continuous, no rest between)
– Or: 5 cycles of: 600m at 10k pace + 1000m at marathon pace

What happens: Small lactate bumps from the fast 400-600m, then clearance during the marathon pace segment. By the end, you’ve accumulated lactate without a single sustained high-lactate effort.

Benefits:
– Upper end of lactate curve becomes more gradual (can sustain higher lactate without sharp rise)
– Trains ability to recover while running
– Less muscular fatigue than continuous threshold

Step 5: Aerobic Intervals (Igloe-Style)

Run short intervals faster than threshold pace but with short recoveries, so lactate doesn’t accumulate excessively.

Examples:
– 10-15 x 400m at 10k pace (or faster) with 100m jog recovery
– 12 x 300m at 10k pace with short rest
– 8-10 x 600m at 10k-half-marathon pace range

Why this works: Trains at faster paces (toward race pace) while staying aerobic due to short intervals and rest periods.

Integration and Sequencing

Different athletes need different emphasis:

5K runner: Move relatively quickly through threshold work toward alternations and aerobic intervals.

10K-marathon runner: Spend more time building threshold base before moving to other formats.

800m runner: Shift quickly to alternations and speed work; threshold is less specific for 800m.

Progression Example (5K Runner, 12-Week Block)

Weeks 1-3: 3-4 x 5-minute threshold sessions with jog recovery
Weeks 4-5: 5-6 x 5-minute sessions with short rest; add one progression at the end
Weeks 6-7: Alternations: 400m @ 10k + 1200m @ marathon pace, 5 cycles
Weeks 8-10: Aerobic intervals: 10-15 x 400m at 10k pace
Weeks 11-12: Blend and maintain; reduce volume as competition approaches

Testing and Monitoring

Without lactate testing, use the talk test:
– Below threshold: Can speak sentences comfortably
– At threshold: Can speak only a few words before breathing hard
– Above threshold: Can’t speak at all

For advanced athletes, lactate testing (if available) removes guesswork and allows precision intensity control.

The Key Insight

Everything works for threshold development: base training, high-end aerobic work, threshold runs, split sessions, alternations, aerobic intervals. What matters is the sequence and the athlete’s specific needs. Build the foundation first, progress through the phases, and adjust based on feedback. Athletes who improve threshold most consistently aren’t those doing the most intense sessions; they’re those progressing intelligently through a structured plan.

See Lactate Threshold Training and The Lydiard Effect for complementary frameworks.