Our guide to the lactate step test
Lactate testing is one of the best ways to fine-tune intensity control. Used well, a lactate meter can help you identify training zones, track progress, and make better decisions in both daily training and structured performance testing.
This is the first article in a short series where we share our best tips on how to get the most out of your lactate meter.
The step test
The step test is designed to help create an individual lactate profile. With a complete lactate profile, we can design a training program that over time can gradually shape that profile to better match your goals.
What is optimal? That depends entirely on your goal and is a topic we may return to in a later article.
Protocol
Start with a warm-up that gets you ready to perform at an optimal level during the test. Then complete 6–8 steps of increasing intensity with 1 minute of rest, including a lactate test between each step.
The warm-up![]()
A standardized warm-up that matches your athletic level is important. For recreational athletes or beginners, that may be a simple jog or brisk walk for 10–15 minutes. For age-group athletes, and even more so for elite athletes, a 15–25 minute warm-up where you move through all relevant intensity zones is recommended.
Test lactate before the warm-up, and again after the warm-up is done. It is important that your post-warm-up lactate is equal to or lower than your pre-warm-up lactate.
Figure 1. Example step test protocol with warm-up, progressive steps, and lactate testing.
The step length
The goal is to ensure that lactate, heart rate, and VO₂ have reached steady state and are representative of each step. However, there is a trade-off between ideal step lengths and the test becoming too long, with fatigue becoming a limiting factor.
Usually, steady state requires a minimum of 5 minutes. For elite athletes, where fatigue is less limiting, each step can be increased to 6–8 minutes. For beginners or recreational athletes, each step may be limited to 3 minutes. Note that 3-minute steps will lead to a skewed profile and may overestimate speed or power at each intensity.
The number of steps and the incremental increase
The aim is to build a full profile and identify LT1 and LT2 in the process. That usually leads to 6 to 8 steps.
Start by estimating where LT2 is likely to occur and aim to reach that point at step 5 or 6. Then choose a starting load that gives 1–2 steps before the first rise in lactate and helps ensure that LT1 can be identified.
Usually, that means an incremental increase of 1–1.5 km/h or 1% incline for runners, and 20–30 W or around 10% of FTP for cyclists. For pool swimmers, a drop of 10–15 seconds per interval is normally optimal.
To get a complete profile, you can consider going all the way to fatigue and ending with 7–8 steps in total, where the last 2 are above LT2.
Recreational athletes: 6–8 × 3 minutes
Age-group athletes: 6–8 × 5 minutes
Elite athletes: 8 × 6 minutes
World-class athletes: 8 × 8 minutes
Interpreting the results
With a lactate step test, we aim to use lactate measurements to identify intensity zones and to have a reference point for tracking development. We aim to identify steady-state lactate levels and use the delta-delta method to identify the lactate thresholds, LT1 and LT2.
Finding LT1
LT1 is the first point at which lactate starts to rise above its stable baseline. In practice, this means looking for the first clear increase, or delta, in lactate from one step to the next. At the lower stages, lactate will often stay flat or change very little. Once you see the first meaningful rise, you are likely at or just above LT1.
Remember, if the test starts too hard, you may miss LT1 entirely. In running, it is also common that LT1 may not be clearly detectable in beginners. That usually means that even easy running starts above LT1.
Finding LT2
LT2 is not just another increase in lactate. It is the highest intensity at which lactate does not continue to accumulate over time. In other words, it is the maximum intensity at which you are still at steady state.
On the curve, this is identified by a much larger increase than in the previous steps. This is why it can be helpful to think in terms of delta-delta. The first delta is the change in lactate from one step to the next. The delta-delta is the change in that change.
In simple terms, if lactate rises only a little from one stage to the next, you are still below LT2. When the increase suddenly becomes much larger, you are likely around or just above LT2.
Figure 2. Example lactate curve showing LT1 and LT2.
Common mistakes
Let’s end with some common mistakes to watch out for.
Starting too hard: If the first stage is too demanding, you may miss LT1 and lose much of the value of the test.
Too short steps: Short steps may not allow lactate to stabilize. This can make the profile look shifted and may overestimate threshold speed or power.
Increments that are too large: If each step increases too much, it becomes harder to identify the actual turning points.
Inconsistent sampling: Inconsistent timing of sampling, poor blood flow, sweat contamination, or squeezing the finger too much can affect the reading.
Looking at single values instead of trends: A single lactate reading is rarely the answer. The shape of the curve matters more.
By Alexander B. Skeltved
DU KAN AUKA
