If you only track one physiological marker as a cyclist, make it your lactate threshold. So, what is lactate threshold? It is the exercise intensity above which lactate starts accumulating in your blood faster than your body can clear it. Below it, you can ride for hours. Above it, the clock starts ticking, your legs fill up, and you eventually blow up. Every World Tour team I have worked with builds its training around this single concept, because it predicts how long you can hold a given power far better than VO2 max does.
This guide covers what lactate threshold actually is (and what it is not), how the main threshold models differ, how to find yours with a field test or a lab, how to pace it in a race, and exactly how to train it. If you want your numbers straight away, use our FTP calculator and power zones calculator alongside this article.
What Is Lactate Threshold? The Short Version
Your muscles produce lactate continuously, even at rest. During easy riding, production is low and your body clears it as fast as it appears, so blood lactate sits around 1 to 2 mmol/L. As you push harder, production rises, and at some point clearance can no longer keep up. That tipping point is your lactate threshold.
Two points matter in practice:
- Lactate is not the villain. It is a fuel your heart, brain, and slow-twitch muscle fibres burn happily. It is a marker of intensity, not the cause of fatigue. The burn you feel is mostly the hydrogen ions and metabolic by-products that accompany high-intensity work.
- Threshold is a zone, not a line. Lab protocols describe two distinct transitions, and the "threshold" you use for training sits somewhere between them.
For a deeper look at the science of threshold models, the review "Lactate threshold concepts: how valid are they?" by Faude and colleagues is a good starting point. It shows why different protocols give different numbers and why consistency in how you test matters more than which model you pick.
LT1 vs LT2: The Two Thresholds That Matter
LT1: the aerobic threshold
LT1 is the first sustained rise in blood lactate above resting baseline, usually around 1.5 to 2 mmol/L. It lines up closely with the first ventilatory threshold and with the top of what most coaches call Zone 2. Riding at or just below LT1 is the foundation of aerobic base work. Most well-trained cyclists can sit here for four to six hours.
LT2: the anaerobic or "functional" threshold
LT2 is the point where lactate rises sharply and no longer stabilises. It is usually 3 to 5 mmol/L depending on the athlete and the method, and it is the intensity people loosely call "threshold". It is the highest power you can sustain in a metabolic steady state, typically for 30 to 60 minutes in a trained rider. In practical terms it is very close to what we measure as FTP.
Where do OBLA, MLSS, and FTP fit?
You will see several overlapping terms:
- OBLA (onset of blood lactate accumulation): a fixed 4 mmol/L cut-off. Simple, but it ignores individual differences. A rider whose lactate sits unusually high or low will get a misleading number.
- MLSS (maximal lactate steady state): the highest intensity at which lactate stays stable over 30 minutes. It is the gold standard but requires several lab visits.
- Critical power: a mathematical model of the power-duration curve. It sits slightly above MLSS and is a useful bridge between lab physiology and field data.
- FTP (functional threshold power): a field estimate of the best average power you can hold for roughly an hour. It is a practical stand-in for LT2, not an identical measurement. Our guide on what FTP is in cycling goes deeper.
The takeaway: these numbers will not match perfectly. Pick one method, test the same way each time, and track the trend.
Why Lactate Threshold Predicts Performance Better Than VO2 Max
VO2 max sets your ceiling. Lactate threshold determines how much of that ceiling you can use. Two riders with identical VO2 max can differ by 15 to 20 percent in sustainable power because one clears lactate more efficiently and works at a higher fraction of his or her aerobic capacity.
The classic work from Edward Coyle and colleagues in the late 1980s and early 1990s showed that among trained cyclists, performance in prolonged events correlated more strongly with the power or speed at lactate threshold than with VO2 max (search the Coyle papers on PubMed). If you want to understand the aerobic ceiling itself, read our guide on how to improve VO2 max, and our walkthrough of the VO2 max test.
It also explains something I see weekly with coached athletes: a rider can improve threshold by 20 watts without VO2 max moving at all, and race results change dramatically. In a long climb or a time trial, you are living at threshold, not at VO2 max.
What Determines Your Lactate Threshold?
Threshold is trainable, but the drivers are worth knowing because they shape how you train:
- Mitochondrial density and function. More and better mitochondria mean more oxidative capacity, so less reliance on glycolysis at a given power and lower lactate production.
- Capillary density. A richer capillary network delivers oxygen and clears lactate faster.
- MCT transporters. Monocarboxylate transporters shuttle lactate out of working fibres and into others that can use it. Training upregulates them.
- Muscle fibre type. A higher proportion of type I fibres generally means higher threshold relative to VO2 max.
- Substrate use. Riders with strong fat oxidation spare glycogen and produce less lactate at submaximal loads. This is why low-intensity volume matters even for threshold-focused riders.
- Fatigue, heat, altitude, and nutrition. Low glycogen shifts the lactate curve; heat and dehydration drop sustainable power regardless of your actual threshold.
How to Find Your Lactate Threshold
Option 1: Lab testing with blood lactate
A graded test on a trainer or ergometer is the most informative option. You ride in stages, typically three to five minutes each, with a small blood sample taken at the end of every stage. Plotted against power, the lactate curve reveals LT1, LT2, and the shape of your curve. The shape is gold: a curve that stays flat and then rises steeply tells you something very different from one that creeps up gradually, and it tells me where to focus training.
Expect to pay a modest fee at a university or performance lab. Test every 8 to 12 weeks in a build phase if you want to see the effect of training.
How to read your lactate curve
Three patterns come up constantly. A rider with a low, flat curve that turns up late has a strong aerobic engine but may lack top-end power, so we add VO2 max and anaerobic work. A rider whose curve starts climbing early has a high glycolytic contribution, so we lean on Zone 2 volume and sweet spot to move the whole curve right. A rider with a steep rise after threshold but a good LT1 usually needs more time at and just above threshold to improve lactate clearance. Same FTP, three very different training prescriptions.
Option 2: Field test for FTP
For most riders, a field test is enough. Use the 20-minute protocol:
- Warm up for 20 minutes with three 1-minute efforts at a hard pace.
- Ride 5 minutes all-out to pre-fatigue the legs, then recover for 10 minutes easy.
- Ride 20 minutes as hard as you can sustain evenly. Do not start too fast.
- Multiply your 20-minute average power by 0.95 to estimate FTP.
The 0.95 factor is a convention, not a law. Strong time-trial riders may be closer to 0.92 to 0.93, and punchy riders without much endurance may exceed 0.95 in a 20-minute test but fall short over an hour. Take your result and run it through our FTP calculator to see how it translates into training numbers.
Option 3: Heart rate and the talk test
No power meter? Your lactate threshold heart rate (LTHR) is the average heart rate of the final 20 minutes of a 30-minute maximal solo effort. For a first pass, use the heart rate zones calculator to set zones from your result. The talk test also works as a rough guide: at LT1 you can speak in full sentences, at LT2 you can only manage a few words.
Heart rate lags behind effort and drifts with heat, caffeine, and fatigue, so power is always the better control variable when you have it.
Your Lactate Threshold Training Zones
Once you have FTP, you can set power zones. These are the standard seven-zone percentages, with the threshold zone in bold:
- Zone 1, Active Recovery: under 55% of FTP
- Zone 2, Endurance: 56 to 75% (this is where LT1 sits)
- Zone 3, Tempo: 76 to 90%
- Zone 4, Threshold: 91 to 105%
- Zone 5, VO2 Max: 106 to 120%
- Zone 6, Anaerobic Capacity: 121 to 150%
- Zone 7, Neuromuscular Power: maximal efforts
Our cycling power zones calculator works out all of them from your FTP.
How to Improve Your Lactate Threshold: What the Evidence Says
Threshold responds to three things: more aerobic volume, targeted work near threshold, and a smart intensity distribution.
The elite endurance model is well documented. Stephen Seiler's analyses of top rowers, runners, skiers, and cyclists found that most world-class athletes spend roughly 75 to 80 percent of training time at low intensity and about 15 to 20 percent at high intensity, with comparatively little time in the grey zone between (Seiler's work on PubMed). A controlled comparison by Stöggl and Sperlich in 2014 found that polarised training produced larger gains in VO2 peak and time-to-exhaustion than threshold-only or high-volume low-intensity training in a group of well-trained endurance athletes; you can find it by searching PubMed.
What does that mean for your threshold specifically? In my experience coaching amateurs through to professionals:
- Build the base first. Zone 2 volume raises mitochondrial density and fat oxidation, both of which push the entire lactate curve to the right.
- Layer threshold work on top. Two quality threshold sessions a week is plenty for most riders. More than that and you accumulate fatigue without a matching adaptation.
- Add some VO2 max work. High-intensity intervals raise the ceiling so that your threshold, as a percentage of that ceiling, has room to grow.
- Recover. Adaptations happen between sessions. An easy week every third or fourth week keeps the quality high.
5 Lactate Threshold Workouts You Can Do This Week
All wattages are percentages of your current FTP. Warm up for 15 to 20 minutes before every session and cool down for 10 minutes. If you ride indoors, our guide to indoor cycling workouts has more trainer-friendly sessions.
1. Classic Sweet Spot: 3 x 15 minutes
Intensity: 88 to 94% of FTP. Recovery: 5 minutes easy between intervals.
Sweet spot sits just under threshold. It delivers a large aerobic stimulus with less fatigue than true threshold work, which makes it ideal for building volume at high load early in a block. Progress to 2 x 30 minutes over four to six weeks.
2. Threshold Intervals: 4 x 10 minutes
Intensity: 95 to 100% of FTP. Recovery: 5 minutes at Zone 1.
This is the bread-and-butter threshold session. Hold power as steady as possible: the first interval should feel controlled and the last should feel hard. If you cannot finish the fourth, your FTP is probably set too high.
3. Over-Unders: 3 x 12 minutes
Structure: alternate 2 minutes at 95% FTP with 1 minute at 105% FTP, four times per set. Recovery: 6 minutes easy.
Over-unders train your body to buffer and clear lactate while still working. You ride above threshold, generate lactate, then drop to just below it and learn to process it without slowing down. They are the most race-specific threshold workout for punchy courses and breakaways.
4. Long Threshold Effort: 2 x 20 minutes
Intensity: 98 to 102% of FTP. Recovery: 10 minutes easy.
The classic time-trial prep session. It builds the mental and physical ability to sit at threshold for as long as the race demands. Do this once every one to two weeks in a threshold-focused block.
5. Micro-Intervals: 3 x (8 x 30 seconds on / 15 seconds off)
Intensity: 120% of FTP on, easy spinning off. Recovery: 5 minutes between sets.
Short on-off intervals let you accumulate a lot of time close to VO2 max with manageable fatigue. They also lift threshold indirectly by raising your aerobic ceiling. Use them in weeks where you want a hard session but cannot sustain a long threshold effort.
A Simple 4-Week Threshold Block
Here is a template you can adapt. Fit the easy rides and rest days around your life and keep two hard days apart by at least 48 hours.
- Week 1: Tuesday 3 x 15 sweet spot, Thursday 4 x 8 at 95 to 100% FTP, Saturday 3 hours Zone 2.
- Week 2: Tuesday 3 x 20 sweet spot, Thursday 4 x 10 threshold, Saturday 3.5 hours Zone 2.
- Week 3: Tuesday 2 x 30 sweet spot, Thursday 3 x 12 over-unders, Saturday 4 hours Zone 2 with 2 x 15 tempo.
- Week 4 (recovery): Tuesday 2 x 15 sweet spot, Thursday 30-second micro-intervals, Saturday 2 hours easy. Retest FTP at the end of the week.
Most riders gain 3 to 7 percent on FTP over a block like this if they are consistent and not coming off peak form. Beginners often gain more, while experienced riders see smaller steps and need patience. If you want the next step after that, see our article on building and testing FTP.
Pacing at Lactate Threshold in a Race
Knowing your threshold is one thing. Using it is another. In a 30 to 60 minute climb or time trial, the winning strategy is almost always even power at 95 to 102 percent of FTP, depending on duration. Go 10 percent over in the first five minutes and you pay it back with interest, because every minute above threshold taxes the finite work capacity you have above it, which is why the concept of W' is so useful to coaches.
A few rules I give athletes:
- For a 20 minute climb, aim for roughly 105 percent of FTP and cap the first two minutes at 108 percent.
- For a 40 to 60 minute effort, sit at 97 to 100 percent and resist the urge to bank time early.
- On rolling terrain, ride the flats and descents slightly under threshold and the climbs slightly over, so average power lands on target. Average power matters more than any single section.
- Watch for cardiac drift. If your heart rate climbs steadily at constant power, you are either dehydrated, overheating, or beyond your true threshold.
Practise these numbers in training. Threshold intervals are rehearsals for race pacing as much as they are physiological stimulus.
How Long Does It Take to Raise Your Lactate Threshold?
Expect measurable change within four to eight weeks of consistent training. Untrained and recreational riders can see 10 to 20 percent increases in the first season. Well-trained riders usually progress 1 to 3 percent per block, and elite riders fight for 1 percent a year. Threshold also detrains slowly over a couple of weeks of rest but drops faster over several weeks off the bike, so consistency beats heroics.
Common Mistakes When Training Lactate Threshold
- Riding every session in the grey zone. Zone 3 tempo feels productive but, ridden for all your easy days, it blunts recovery and caps how hard your hard days can be.
- Using an outdated FTP. If your intervals feel too easy or too hard, retest. Accurate zones are the difference between productive and wasted training.
- Starting intervals too hard. Threshold intervals should be even, not a race to the first minute.
- Skipping the base. A narrow aerobic foundation limits how much threshold work you can absorb.
- Chasing lactate numbers alone. A lactate curve is a diagnostic. It does not replace consistent riding, nutrition, and sleep.
- Underfuelling. Threshold sessions burn a lot of carbohydrate. Eat before and during sessions longer than 60 minutes.
- Ignoring overreaching. Two threshold sessions a week for many weeks without a recovery week is how riders end up flat, with power falling and resting heart rate rising.
Frequently Asked Questions About Lactate Threshold
Is lactate threshold the same as FTP?
Not exactly. FTP is a practical estimate of your power at LT2, derived from a field test. Lab-measured thresholds can differ by 5 to 10 percent, depending on the protocol, but for training purposes FTP works well.
Does lactate threshold decline with age?
Threshold power tends to drop with age, but the decline is gradual and heavily influenced by training. Riders who keep training consistently maintain threshold well into their 50s and beyond.
Can I raise my threshold without a power meter?
Yes. Use heart rate zones and perceived effort. Sustained, steady efforts at a hard but controlled pace work. A power meter simply makes the effort more precise and your progress easier to measure.
How often should I test?
Every 6 to 8 weeks is a good rule of thumb, ideally at the end of a recovery week so you are fresh.
Put Your Threshold to Work
Knowing what lactate threshold is only helps if you train it correctly. The right workouts, the right zones, and the right recovery separate riders who plateau from those who keep improving season after season.
If you want a structured path, our tailored training plans are built around your threshold, schedule, and goals. And if you want a coach in your corner who has worked with professional riders, you can apply for coaching here. Start by testing your FTP this week, set your zones, and complete one of the workouts above. Your threshold will tell you what to do next.
