If you want to learn about lactate testing, you’ve come to the right place.

In this resource, you’ll learn everything you need to know, from the basics of lactate as a molecule, all the way to lactate testing for athletes, what kinds of lactate tests exist, and even what lactate testing kits are available.

To make your navigation easier, we’ve included a table of contents linking to the different sections of this lactate testing guide.

What is Lactate?

Lactate is an important molecule of human metabolism. At its base, it is simply the byproduct of glycolysis. Glycolysis is the process of breaking down sugar molecules (glucose or glycogen) to recycle energy inside the body.

Muscle Fatigue

For a long time, we blamed lactate for causing muscle fatigue. Instead, it turns out that lactate is an important fuel for our mitochondria. In addition to being a source of energy, it’s also an important signaling molecule inside the body.

Lactate Production

Interestingly, we produce lactate even at rest when oxygen availability is high. It is also the main gluconeogenic precursor inside the body. This means that it will help recreate glucose molecules. This takes place inside the liver via the Cori Cycle. For instance, about 30 percent of all glucose used during exercise actually comes from lactate.

A Metabolic Fuel

As illustrated by George Brooks in the seminal paper “Lactate in contemporary biology: a phoenix risen“, Lactate is the fulcrum of metabolism. To put it another way, lactate is the link between glycolytic metabolism and oxidative metabolism. Indeed, energy systems are all coupled together and work synergistically inside the human body.

Lactate Rises during Exercise

During exercise, lactate rises as the intensity increases. By measuring lactate (via lactate testing), we can optimize training, target different training adaptations, and more.

Let’s learn more about lactate testing.

What is Lactate Testing?

Initially reserved for laboratories, lactate tests can now be performed in the gym, at home, or in the field. During a lactate test, the athlete (or the coach/tester) collects blood samples using a lancet and a lactate analyser. The lancet punctures the skin and makes the drop blood accessible. The lactate analyzer supports disposable strips. It’s imperative to change the lactate strips after each sample.

Given the invasive nature of the test, the person performing it should wear sterile and protective gloves. Common sampling spots are the finger and the earlobe. Therefore, if you administer a test to yourself, using the finger for the lactate sample is the most viable option.

What is the Goal of a Lactate Test?

The goal of a lactate test is to look at how lactate accumulates in the blood along the intensity spectrum. Unlike VO2 (oxygen consumption), blood lactate increases in a non-linear fashion. By plotting lactate against intensity (watts for cycling and speed for running, for example), we look for two major inflection points in the lactate curve. Those inflection points reflect changes in the body’s internal state. We commonly call them “thresholds” (or “lactate thresholds”).

Knowing the lactate thresholds allows us to individualize training intensities for the athlete. Athletes who use training intensities based on their physiology ensure that each hour of training is moving them closer to their goal.

Another reason to perform a lactate test is to track progress over time. The athlete can perform a lactate test after important training blocs in order to quantify the effect the training had on their physiology. This can also help orient future training decisions based on the athlete’s profile, their strengths, weaknesses, and specific needs.

Besides lactate threshold tests, other kinds of lactate tests exist. You can, for example, measure your ability to clear lactate (“lactate clearance”) or even measure the athlete’s physiological response during a training session.

Heart Rate vs Lactate

Speaking in broad terms, the heart rate rises linearly with intensity (see graph above). Consequently, we will not see significant changes in the HR trend (inflection points) in the same way we do with lactate. For that reason, we shouldn’t use heart rate instead of lactate. We should rather use heart rate along with lactate.

By measuring lactate, intensity, and heart rate during the lactate test, we increase the precision of our monitoring.

Lactate Testing for Endurance Performance

In endurance sports such as cycling or running, having a high lactate threshold is an important performance factor. Essentially, a high lactate threshold means that you can use a large fraction of your VO2 max while maintaining an internal steady state. In that way, you’re able to exercise for extended periods of time without going “into the red zone”.

For this reason, accurate lactate testing is a way to individualize training intensities and optimize performance in a very concrete way.

Individual Lactate Responses in Athletes

Many factors influence an athlete’s lactate response.

For example, genetics has an important effect on fiber type distribution. These fibers (Type I, IIa & IIx) have different metabolic profiles. This means that they employ different strategies to recycle ATP. While Type I fibers have a high mitochondrial and capillary density (high oxidative capacity), Type 2 fibers will be more inclined to rely on glycolysis. If an individual carries a lot of muscle mass (usually linked to a higher T2 fiber proportion), they will likely display higher glycolytic activity (and lower oxidative activity) compared to someone with the opposite profile.

An athlete’s training background will also have a significant impact on their lactate response during exercise. Someone who has trained for many years in endurance sports will often exhibit a high oxidative capacity, leading to lower blood lactate values at a given speed or power. This lactate profile is very different from that of someone who trained for many years in a power sport with very little endurance training.

Lactate Threshold Testing Protocols

We can use different testing protocols along with lactate sampling. Each protocol has its own specific aim and should be chosen according to the context of the athlete being tested. Below you will find a few different popular protocols aimed at highlighting different facets of the athlete’s physiological profile.

Lactate Step Test – Lactate Threshold Testing

A step test is a protocol that has the athlete go through a range of different intensities, often starting low and finishing high. In the context of lactate testing, interval durations of 4-10 minutes are recommended. Some prefer to include short rest intervals between each stage, while others don’t. The rest intervals, if used, allow the coach or the athlete to take better lactate samples.

The test should begin at a very low intensity (1/10 or RPE1). That way, the risk of missing the first lactate threshold (LT1) will be minimized. At the end of each work stage, the athlete or the coach samples the lactate from the earlobe or from the finger. This protocol should ideally last around 10 stages in order to get a complete view of the athlete’s metabolic profile.

Choosing the Right Lactate Threshold Testing Protocol

If the number of steps performed is much smaller than 10, the large power/speed increases between stages will make the interpretation less precise. Conversely, if the step increases are too small, the test might last a very long time. The key is to calibrate the test according to the athlete’s abilities. That way, we can find the best compromise between power increase between steps and total test duration.

This protocol can be used by beginners and elite athletes alike. The main objective is to determine the athlete’s lactate thresholds 1 & 2. Using this information, we can then individualize training intensities and orient the athlete’s training according to his/her strengths and weaknesses.

We should remember that these lactate thresholds aren’t perfect. However, they serve as a good model to break up the intensity spectrum into distinct domains. That way, we can more easily plan different types of training for the athlete.

Maximum Lactate Steady State – Lactate Threshold Testing

Maximum Lactate Steady State (MLSS) is defined as the highest workload (expressed in watts or speed) that can be maintained while blood lactate remains “stable”. Depending on who you ask, stable has varying definitions. For some, any increase in BLa over time indicates that the athlete has exceeded MLSS. Others allow a 0.9 mmol/L increase between minutes 10 and 30 of a 30-minute continuous effort. Needless to say, coaches use many different ways to determine MLSS.

When compared to the lactate step test described above, the MLSS test comes out on top in the precision department. Indeed, LT2 or lactate threshold is supposed to discriminate between stable and non-stable internal states. However, since the MLSS protocol requires multiple efforts of 30 minutes in duration, it is quite time-consuming. There have been attempts to come up with a one-day MLSS test protocol.

Theoretically, MLSS identifies the balance between lactate production and lactate clearance. This usually equates to the intensity that an athlete can sustain for 40 to 70 minutes. By knowing this steady-state value, we can be more precise when prescribing threshold training sessions for our athletes.

VLa Max Testing (Max Glycolytic Power)

VLa Max is meant to indicate the maximal production rate of lactate in your muscles. Note that we can only measure lactate in the blood so this is an imperfect metric. However, it can be a useful metric to help coaches track an athlete’s full metabolic profile.

The VLa Max test (also called glycolytic power or anaerobic capacity) should be performed when well rested. A 10-15′ active recovery phase should precede the VLa Max test. Once BLa is below 2.5 mmol/L, the test can begin.

The coach or athlete should take a lactate sample before the max effort sprint. Once the baseline value is known, the athlete performs an all-out effort for 10-15 seconds. Be sure to set the bike with a high enough resistance so that the athlete doesn’t spin out (not enough resistance) when expressing his/her max power.

After the 10-15-second effort, the athlete rests passively. That way, active recovery won’t influence the lactate values. We collect the lactate samples at minutes 3, 5, and 7 AFTER the sprint. If the readings keep increasing, more samples should be taken. The goal is to find the highest lactate value.

Calculating your VLa Max

We can then calculate the VLa Max by subtracting the baseline value (e.g. 1.5 mmol/L) from the max lactate value (e.g. 15.6 mmol/L). Then we divide the result by 16. This gives us a rough estimate of how powerful the athlete’s glycolytic system is. If we decide to also take one last sample 20 minutes after the test, we can calculate a lactate clearance rate.

The calculators below help you determine your VLa Max and your Lactate Clearance Rate. Coaches and athletes can also use dedicated software such as INSCYD to perform those tests and calculations. It is worth noting that the initial research conducted on this protocol required a very specific erg bike with precise resistance parameters. It might not be as accurate or useful when used outside of this context.

Lactate Graph Interpretation

Following a lactate step test, the coach (or the athlete) needs to interpret the data. The difficult part of lactate graph interpretation is that there exist many methods to do so. The graph below illustrates the different interpretation methods known today.

I personally use Bsn + 0.5 to find lactate threshold 1 and ModDMax to determine lactate threshold 2. From my perspective, there is no better or worse method. However, you MUST take the strengths and weaknesses of the chosen methods into account when you plan training around those values. You can find a detailed breakdown of different lactate curve interpretation methods here.

Lactate Testing Kit

In this section, I will compare different lactate testing devices available on the market. Lactate analyzers usually require disposable strips. You can only use each strip once. The strip serves as the interface between the blood droplet and the device. You can buy a lactate testing kit for anywhere between $200 and $350 depending on the model and the reseller.

Lactate Scout 4 – Lactate Testing Kit

Lactate Plus Meter – Lactate Testing Kit

EDGE Lactate Meter – Lactate Testing Kit

Lactate Pro 2 – Lactate Testing Kit

Lactate Analyzer Comparison Table

In this table, I will provide a side-by-side comparison of the different lactate testing devices and their characteristics.

Characteristic	Lactate Scout 4	Lactate Plus Meter	EDGE Lactate Meter	Lactate Pro 2
Price	$365	$312	$200	$340
Measurement Time	10 seconds	13 seconds	45 seconds	15 seconds
Strip Cost	$2-2.5/strip	$1.9/strip	$1.9/strip	$1.9/strip
Measurement Range	0.5-25 mmol/L	0.3-25 mmol/L	0.7-22.2 mmol/L	0.5-25 mmol/L
Blood Sample Size	0,2 µl	0,7 µl	0,3 µl	0,3 µl
Memory Capacity	500	130 results	300 results	330 results
Altitude Limit	4000m	4000m	4000m	4000m
Device Weight	60 g	75 g	64 g	50 g
Order Analyzer	Order Now	Order Now	Order Now	Order Now

VO2max Testing VS Lactate Testing

VO2 max is the maximum amount of oxygen that the body can consume. As intensity goes up, so does our oxygen consumption until we reach VO2 max. The unit of measure for VO2 max is either in L/min if expressed in absolute terms, or ml/kg/min if expressed in relative terms. We can perform different kinds of VO2 max tests depending on what information we wish to garner.

A common test to determine an athlete’s VO2 max is a short ramp test lasting 9-15 minutes and completed to exhaustion. During this test, we increase the power/speed every minute which eventually elicits VO2 max. While a high VO2 max is a prerequisite for elite endurance performance, I would argue that in isolation, it is a less valuable metric than well-determined lactate thresholds.

You can however measure both. During my complete physiological tests, I measure the following:

• Spirometry
• VO2 and VO2 max (using VO2 Master)
• Ventilation (how the athlete breathes)
• Lactate
• Muscle oximetry (using Moxy Monitor)
• Heart rate
• RPE (Rating of perceived exertion)

If we possess a tool that can measure CO2, it is possible to extract more precise ventilatory thresholds than with VO2 and ventilation alone. In that regard, VO2 testing is complementary to lactate testing. However, if the aim is to individualize the athlete’s training and track their metabolic development, I would argue in favor of lactate testing over VO2 max testing.

Limitations of Lactate Testing

While lactate testing is a great option for athletes wanting to individualize their training and track their progress, we need to be aware of the limitations of this approach.

First of all, a new user is likely to make mistakes during the lactate sampling phase. Because blood samples are very sensitive to contamination (for example from sweat), we must make sure our preparation and our sampling procedure are well rehearsed and executed. I recommend that an athlete practice taking multiple samples before engaging in a complete lactate test.

Secondly, we need to consider the error margins of lactate analyzers. While they are of great quality and accessibility, we should not take their readings as absolute and perfect.

Thirdly, lactate results are sensitive to numerous factors such as fatigue, stress, caffeine intake, time of day, nutrition, and more. We should always consider this important fact when performing a lactate test and do our best to control as many of those parameters as possible. The best we can do is to follow a standardized procedure in the hours preceding the test to increase our chances of success.

Why Lactate Testing is Imperfect

We also need to be aware of the fact that no lactate testing protocol is perfect. Each protocol has its pros and cons, its strengths and its weaknesses. If you want to get the most out of your testing, you need to know WHY you are using a given protocol and WHAT its limitations are. The better you know your protocol’s limitations, the more equipped you will be to use the results in a concrete way.

Finally, it is the muscle cells that produce lactate. This means that by the time lactate makes its way into the bloodstream, many things can and have happened to it. Learning from the lactate shuttle concept, we know that lactate can be transported to different locations inside the producing cell. Lactate can also be transported (or shuttled) to adjacent cells to be used as fuel. Our liver will convert lactate back to glucose. Our brain and our heart will also use it as fuel. Each individual will produce, transport, and oxidize lactate in different ways.

To sum up this section, it is true that lactate testing has many flaws. We should consider each point carefully before engaging in lactate testing. That being said, it remains, in my opinion, one of the best testing options accessible to athletes today.

Lactate Testing in Running

Runners can perform lactate tests on a treadmill or on the track. I like to start runners at a really easy pace (6-7 km/h) and increase by anywhere from 0.5 to 1 km/h on each step. If I’m testing advanced male runners, we will likely start at 10 km/h and increase by 1km/h on each step. We sample the lactate after every step. We also look at heart rate and RPE (rating of perceived exertion) at the end of every step.

For runners, we express the lactate thresholds as both a running speed and a heart rate. They can then base their training intensities on those values. Most runners tend to run their easy runs too fast. A lactate test enables them to more accurately target the right adaptations and get the most out of their training.

Some runners also use lactate during training, especially during lactate threshold training sessions. Different coaches have different approaches to this practice, but you can find a great article about the Norwegian method here.

Lactate Testing in Cycling

Power-based testing (like “FTP” testing) is fairly common in cycling circles. Using this approach, the athlete uses a performance metric (e.g. max average power over 20 minutes) to estimate the lactate threshold. From that single data point, power “zones” are calculated as percentages of this P20 (power over 20′). The main limitation of this approach is that it doesn’t account for individual differences. What I mean is that two athletes with the same P20 might have significantly different first thresholds. This has a significant impact on intensity distribution and how training is performed for each athlete.

By using a lactate test in cycling, athletes can more confidently set their training intensities knowing that these are based on their own physiology rather than a set percentage of an (arbitrary) performance measure. Lactate tests can be performed on the road or on a home trainer. There can be significant differences between indoor and outdoor riding. This should be taken into account when testing and when training as well. Testing lactate using a calibrated power meter and a heart rate strap will provide the most useful results.

Lactate Testing in Triathlon

Training for triathlons essentially means you have to train for three different disciplines. As we saw in previous sections, athletes can benefit from using individualized training intensities that are based on their unique physiology. This adds a layer of difficulty since a triathlete has to (ideally) test himself in each discipline to train appropriately.

Contrary to what some might think, we cannot simply test a triathlete on the bike and transfer his/her heart rate zones to the run or swim. We can cite three different reasons for this: First, the amount of muscle mass involved in cycling, running, and swimming is different. Second, the body’s position in space is different. Running will almost always elicit higher heart rates than cycling simply because of gravity. And thirdly, the muscles don’t contract in the same way in different disciplines. These factors force us to test each modality independently in order to acquire correct and relevant values for training in them.

https://youtu.be/A4U80pXvafo

Performing a lactate test in running and cycling for a competitive triathlete is a no-brainer. If you dedicate large amounts of time to your training each week, you should at the very least train using accurate values. However, performing a lactate test in the swim is a different story. Because of the technical skill that swimming requires, I advise triathletes to first work with a swim coach and focused on the development of a strong foundation in swimming technique. Once the technical aspect is taken care of, we ca perform a lactate test in the pool.

Learn more about the Norwegian triathlon team’s approach to lactate testing.

Lactate Testing in CrossFit

For many, CrossFit is NOT an endurance sport. I agree that most CrossFit competitive events fall short of the typical endurance sport time domain. That being said, we should highlight the demands imposed by training for the sport itself, rather than the competition alone. Indeed, being good at CrossFit requires athletes to develop a wide range of technical and physical qualities. This takes a lot of time. And when we talk about training time, we HAVE to talk about endurance.

Endurance training allows the CrossFit athlete to train more, to train harder, and ultimately to perform better in their sport. In light of that fact, lactate testing becomes a potent tool for the CrossFitter who wished to improve their work capacity, their recovery, their fatigue resistance, and their metabolic conditioning.

I’ve been fortunate to work with many CrossFit competitors. The overwhelming majority report a very significant transfer of the general endurance training I prescribe (mainly performed on the BikeErg) over to their training and their sport. While Metabolic Conditioning forms the foundation of the CrossFit Pyramid (above nutrition), many have left this aspect aside in favor of high-intensity “WODs” performed multiple times per week. The consequence of this is that most CrossFit athletes have an endurance deficit.

High-intensity training is a strong stimulus for beginners, but intermediate and especially advanced athletes need a more balanced training structure. Lactate testing thus gives the athlete the ability to train at the right intensities to continue their metabolic development.

Upside Strength Lactate Testing: Protocol 41

Put simply, Protocol 41 is the best compromise I’ve found in terms of lactate testing protocols. Using Protocol 41, I’ve been able to test athletes across many sports and successfully individualize and optimize their training. I’ve been lucky to work with cyclists, runners, triathletes, rowers, sailors, CrossFit competitors, MMA athletes, boxers, volleyball players, soccer players, handball players, and more.

If you want to perform a lactate test with Upside Strength, you can contact us here.

If you want to learn more about how you can apply Protocol 41 to improve your own conditioning, visit the Protocol 41 presentation page.

Frequently Asked Questions about Lactate Testing

Additional Resources on Lactate Testing

Conclusion

I hope this guide has answered your most pressing questions about lactate testing for athletes. Despite its limitations, lactate testing remains a time-tested and sound way to individualize training, track progress, and inform training decisions.

If you’d like me to cover other aspects of lactate testing, feel free to contact me directly.

Happy testing, and happy training!

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