The Measure of Training Intensity Through Lactate

Courtesy of Arilson Champam, Aquatics Center Director/ Head Swim Coach at Montverde Academy- Florida.

The measuring of lactate to determine the intensity of the exercise during training provides ways to link the activity to three different systems of releasing energy in muscles.

Lactate fuels the intensity of training, supplying information of how exercises start the metabolic system process.

It is possible to relate the adaptations provided by training the metabolic characteristics and the muscular activity during training. The lactate test can supply the swimmer, in an individual way, with information of biological adaptation expected in relation to the exercise during training.


For the lactate test to yield safe and important results, assure yourself that:

1)    The test will be executed for the specific sport, so it will be a specific style.

2)    A higher concentration of lactate post-exercise will be used as criteria for evaluation.


Tests done by the swimmer, for example, on a biometric bike, does not provide sufficient information about the conditioning of the specific event of the swimmer. In fact, there is no scientific evidence that a swimmer with a charge (watt/kg) higher than four mmol/l on the bike will swim faster at a charge of four mmol/l

The velocity of a simmer with a charge at 4 mmol/l is important to estimate the intensity of training, to be able to perform in competitions. However, a charge of four mmol/l does not supply any guarantee performance in competitions or during training while swimming.


Swimmers that swim back, breast strokes and butterfly should be tested in their own style if the coach should want, so that through further reading of the lactate test, improves, respectively the training of back, breast strokes, or butterfly. In fact, even though there is a difference in velocity at a charge of four mmol/l (V4) in freestyle, approximately, the correlation between the speed in freestyle and back, breast, and butterfly strokes cannot be transferred one to the other. The correlation is too low to tell the difference in the quality of aerobic endurance in back, breast, and butterfly stroke to freestyle.


To conduct a safe test it is important to get arterial blood (from an ear lobe or a fingertip) to get the highest concentration of lactate in the blood (it is highest after exercise), only this can determine how much lactate the muscles are producing.

The lactate moves it self from the muscles to circulate the blood stream, where it is finally measured, there is a difference between the when the highest concentrations are present in the muscle and when they are present in the blood. There for two samples should be taken after exercise to get the highest concentration in the blood.

After swimming at almost full speed and more than 100 m two samples should be taken; the first after the first minute after exercise and the second after the third minute. If the reading is higher than the first then a 3rd sample should be taken, after the 5th minute, additional samples until the lactate levels drop.

At a full speed pace and a shorter distance (more or less 100 m), the levels of lactate will surge later and more samples will be needed. After wards the first sample should be taken at the 3rd minute and every 2 minutes until the lactate levels drop.

Aerobic Capacity – It is very easy to evaluate aerobic capacity. You can assure yourself that any swimmer (sprinter, or long distance) with a high aerobic capacity it can be expected that:

  • Good performance in competitions
  • Submit themselves and adapt to:

– Higher amounts of training

– High intensity training

Longer cycles during the year


With the resulting characteristics above, the aerobic system for releasing energy is very appropriate for high endurance (release of energy over a long period of time, as a final result of metabolism with no negative affects). The more the aerobic system develops, the more oxygen can be used more quickly in the body while swimming, even during prolonged exercise.

The aerobic capacity is important because it is the main factor that determines performance in events of medium and long lengths.

However, the energy released by the aerobic system (due to time) will never be more than the amount of energy released by the anaerobic system.

It is easy to see that the anaerobic systems’ contribution diminishes during exercise. It will never be possible to swim fast during long exercises on during short ones.

So what you’re saying is that a sprinter doesn’t need to have a well developed aerobic system?

It is common to believe that sprinters do not need the same aerobic capacity as long distance swimmers, but this is not true. (Except maybe for events 50m).

Sprinters should possess a strong aerobic capacity, as well as the long distance swimmers.

This is confirmed by comparing elite sprinters and long distance swimmers in a simulation program that indicates that it is essential to have a good aerobic and anaerobic system to perform.

Proving that, there for, sprinters are a more complete athletes than long-distance swimmers.

“World Class” swimmers should combine an excellent aerobic system with an excellent anaerobic system. On the other hand elite long distance swimmers can perform well by having an excellent aerobic capacity and a low anaerobic capacity.

In conclusion, a swimmer with a better aerobic capacity will turn out better results in competitions.

There is also another reason why swimmers should want to reach a stronger level of aerobic capacity:

Results of Training:

  1. An athlete will recover better after intense training, more intense training can be done more frequently over the training cycle without having to wait for recuperation.
  2. Pertaining to competitions the faster the athlete can recuperate the better they will perform on the subsequent during the competition and the ever import actual days of competition.
  3. Other than that the aerobic capacity speeds up:
    • The regeneration of the Creatine-Phosphate (CP) (which begins immediately after exercise)
    • The elimination of the lactate. (Those swimmers with a highly developed aerobic capacity.)
    • The elimination of the lactate during and after training.

This finding has great importance to conduct and interpret readings of the lactate, and how to determine training intensity.

Although it is necessary that the lactate levels return to normal during resting periods, in order to have a full recuperation, other recuperation processes should also be considered.

The contraction in muscles as a result of training, or after a competition which will take a couple days is attributed to the lactate not accumulating in the muscles, but could also be an incomplete recuperation due to biological structures.


The aerobic system is the most trainable system in the three processes of release of energy.

Biological adaptations go side by side with the better of aerobic capacity (growth of the maximum intake of Oxygen), but are complex and slowly occurring. It is necessary, there for, to have a set plan to have enough time do better the aerobic capacity. (In about eight weeks)

The development of aerobic capacity requires a lot of training.

The anaerobic capacity is important to fuel or supplement the energy for the aerobic system, there for it is vitally important to maintain the anaerobic capacity at an appropriate level.

Long distance swimmers that compete in races longer than 1.5 hours, the use of other methods, other than CHO, are greatly beneficial.

There for, even during basic training, during the season, doing both short and intense practices and practices that are long, are made to better the aerobic capacity.

Experience teaches us that training the aerobic capacity should be combined with speed training and training focusing on the development of maximum muscle strength. The negative interference with endurance training and speed training is the explosive power should be minimized but the arm strokes should be kept the same.

With the aim of monitoring anaerobic capacity, the readings given by the lactate will be used in a simulation to calculate the anaerobic capacity. Other observations include the speed of their sprint (max. 25m) the frequency of arm strokes (especially important in breaststroke) although there is insufficient recuperation, of long tasks, could indicate that the anaerobic capacity is diminishing.

Anaerobic capacity – The evaluation of the anaerobic capacity is much more difficult.

First: It should serve exclusively in events that the swimmers should be prepared for, because it decide the level of anaerobic capacity that would be advantageous. A swimmer that swims a 50m for example should have a very high anaerobic capacity (>0.9 mmol/kg/min), a level high enough that proportions the amount of energy being released to be able to keep maximum speed until the end of the 50m. This enormous use of energy, naturally provokes a sudden and powerful, fatigue in the muscles, but since the even only lasts about 22 to 35 seconds, the first signs of fatigue will only be present at the end of the event.

In Longer distance of competitions the anaerobic capacity should be in order (equilibrium) to:

  • Avoid an inhibition of a premature anaerobic system due to fatigue in muscles induced by maximum contributions during a competition.
  • Enable the aerobic capacity to be as involved as possible (maximizing the anaerobic potency)

Second: The evaluation of a swimmers anaerobic capacity also depends on their aerobic capacity. In fact, high aerobic capacity gets much help from the anaerobic capacity. This signifies extra benefits in terms of releasing energy; but more energy will be supplied not only by the aerobic system, but also by the anaerobic before fatigue sets in.

The simulation program estimates:

  • A good anaerobic capacity in relation to a determined aerobic capacity.
  • Races in competition (styles and distances).


The system of releasing anaerobic energy and lactate can be considered an auxiliary system; this system takes care of when the body has a lack of energy at its disposition to maintain the same intensity during training. The percentage of energy used by the anaerobic system and lactate is a big part in prolonging your maximum time of full speed.

In competitions with longer distances the swimmer should prepare themselves as to not prematurely set on muscle fatigue and ultimately slow you down, induced by the additional energy being released. A swimmer should be forced to use the anaerobic lactate system as to prevent the reduction of this supply during races.

In short races a collapse of the supply of energy x velocity could happen earlier during the race – the sprinter that swims the 50m can use his supple of anaerobic lactate energy without worrying about much fatigue during the race. For a 100m race, there should also be no problem except for the beginning of fatigue, because the slow down process only begins after about 50 seconds. But in a 200m race the collapse of this energy x velocity will happen earlier and will give them great difficulty in the second half of the race; if he stays at the same speed the swimmer will inevitably “die down” before he finishes the race.

The science that chooses speeds that use the anaerobic lactate which should be prevented because of premature fatigue (before the final race) inhibited in the sprinter swimmers. There for, the longer the distance, the less the swimmer should use their anaerobic lactate system.

For this reason, in long distance competitions the less this system needs to be developed. This does not mean that long distance swimmers should not develop this system at all. Statistics show that elite long distance swimmers use their anaerobic lactate systems better than less talented swimmers. In shorter competitions, there for means that it is more important for a swimmer to develop a stronger capacity in their anaerobic lactate performance and more time should be spent on developing this capacity.


The pace that is used to better develop the anaerobic lactate energy is based on bettering the capacity of Pyruvic acid. This capacity is referred to as the “anaerobic capacity”. Sometime people confuse the supply of anaerobic lactate energy which is not included in the anaerobic lactate capacity. However, seeing that the trainability of the lactate anaerobic system is very limited, its contribution to a swimmers performance is very low (maybe with exception of the 50m race). That is why “anaerobic capacity” should be called the capacity of Pyruvic acid.

Since the conversion of glycolysis and lactate occurs so quickly the concentration of the pyruvic acid to lactate is 1/1. (“production of lactate = production of pyruvic acid”) it is expressed be the mmol of lactate/ pyruvic acid liter p/ second.

The simulation that shows a faster swim, but with low concentration of lactate is not the result o the best endurance (aerobic capacity), but shows in the weakening of the produce of lactate (anaerobic capacity).

A similar fault could happen with the anaerobic capacity when the anaerobic training is done repetitively and in large amounts, resulting of insufficient recuperation and over compensation, which is a wrong choice in intensity.

When this occurs the swimmer usually loses their anaerobic capacity. Only after about 1 or 2 weeks rest will their aerobic and anaerobic levels go back to normal.



Experience has enabled that statistics be gather on the change in relation of the lactate to the speed of the swimmer using different exercises in training.

You can estimate the concentration of the amount of lactate through distances of 100 200, and 400 m with 10 and 30 second rests it can be used for long distance as well over a period of 20 minutes and a distance of 400m. This estimate is different for males and females and is based on the group average. There for, it is advisable to check the levels through lactate tests during training in case these calculations need to be adjusted individually. This method of calculating let the coach individually give the swimmer a more intense practice in the different training methods in the provisions of that swimmers conditioning in order to reach the desired lactate levels corresponding with the training objectives.

If a swimmer needs to train at 1,2,3,4, or above 4 mmol/l of lactate, with what number of times a week and to what point, depends on the level of conditioning in certain exercises determined by the results of the lactate test.

The conditioning of a swimmer could vary a lot from swimmer to swimmer, the intensity and volume of training should also change individually, even though there are the same objectives in training, even with the same time of training and the same event of competition but to prepare themselves.

For example, long distance swimmers usually have to do resistance training with lower levels of lactate than sprinters with the intent of preventing the overworking of their aerobic anaerobic systems.

These findings are supported with scientific evidence and observations of coaches that work with lactate in training. Note that in sub maximum exercises the sprinter reaches higher amounts of lactate than long distance swimmers and they are less tired and recuperate faster. But, in compensation the comparison between a sprinter and long distance swimmer the long distance swimmer, will have a much higher anaerobic capacity it can vary within swimmers classes.

This way, the coach should estimate the anaerobic capacity of a swimmer in amounts of lactate at small bursts (50 – 100 m)with the lactate of post maximum exercise in a short distance (100 m), using the simulation program with the intent of evaluating the physical impact of exercise to a certain concentration of lactate.

In fact, if there are high levels of lactate registering during short distance tests in training or in competitions, this is sometimes normal in training to get these reading. However, when the maximum reading is low, the training will have to be completed with much care because of the low readings. Other than that swimmers that have a low maximum lactate reading during these short distance tests feel a distortion in intensity of training (the exercises that are hard feel easy) resulting in swimming to fast during practice and setting on unnecessary fatigue. These finding show the importance of the use if the lactate in maximum and sub maximum intensities in practice.


The aerobic resistance (V4 in 400 m) can also be used to indicate how much training a swimmer can take.

In fact, the more their V4, the more practices they can have a week and/or the more distance can be done per practice without overload.

The amount of times an amount of meters, per training session take up most of the training season.

During training camp, the coach takes advantage of the opportunity to have more and longer practices per session. During the resting process, which is very important (not only after training but after ailment as well) after that the amount and lengths of practices will be short as possible.

At the intensity orientation of training through the simulation of V4, should never be less than 2400 m or 20 minutes. Distributed in the following way;

6x 400 m = 2400 m

12x 200 m = 2400 m

24x 100 m = 2400 m

48x  50 m = 2400 m


  • With the base sub maximum velocity freestyle 400m we can easily estimate for various exercises of training the times of swimming correspond to the desired lactate level. The values prove the reach of the targeted intensity and the objective for which they are training for.
  • The levels of lactate that corresponds to the objective of training is not the same for all. In fact, even though they may have the same objective the level of lactate should be adjusted according to the swimmers aerobic and anaerobic capacities.
  • This means taking a different approach to each swimmer even though they have the same amount of time in the season and are preparing for the same event competitively.


Starting from the beginning of the shorter the distance swum, relatively a higher participation of the anaerobic system and, the faster you swim and the more distance you swim, relatively a greater participation of the aerobic system.

The objective of training should be to get perfect equilibrium between these two systems with the intent on reaching the maximum specified speed, also known as maximum performance, on events that the athlete is being trained in.

The capacity of the development of the muscular system is determined mostly by the amount of energy available for muscular activity. The more energy available per unit of time (second), the more intensely the muscle can function (speed of the swimmer). If for any reason less energy is available per unit of time, the muscular intensity will drop causing a decrease in speed. From the metabolic point of view (without any interference in way of swimming or physical change), the best development is proportionate to the total energy supplied by the three systems of distribution of energy; anaerobic ablactate energy + anaerobic lactate energy + aerobic energy.

The lactate is the only metabolic variable that can indicate aerobic and anaerobic capacity in muscles. No other metabolic parameter supplies the same information about the amount of energy the athlete can produce per unit of time. The perfect development of the participation of these systems depends on the even the athlete is training for.

The aerobic and anaerobic capacities and the use of their substructures are interrelated. This relation leads us to postulate three principles in relation to production of lactate in muscle, and are founded upon the intensity, in the absorption of oxygen by the muscles (VO2max – aerobic capacity) and, in the maximum production of lactate by the muscles (V1amax – anaerobic capacity)

Principles of the interaction of the systems:

  1. Principle of intensity – the production of the lactate increases with the increase of effort. In this case even though the level of lactate did not go up in the blood there could have been an increase in the glucose system because the aerobic system is very active and will get lactate from any source that it can find using it as a source of   energy ( production > absorption of lactate).
  2. Principle of aerobic capacity – With the increase of the aerobic capacity the participation o the anaerobic system will relatively smaller to and level of effort.
  3. Principle of anaerobic capacity – With the increase of the aerobic capacity the participation o the aerobic system will relatively smaller to and level of effort.

The athlete at the international level (international elite) shows characteristics fundamentally different than those athlete of a medium level such as, high aerobic capacity, high elimination of lactate (anaerobic capacity and tolerance of the lactate) and the economization of movement. There for, the physical adaptations, generally applied to medium level athlete, are not necessarily the same as an international level athlete.

The muscularity of a trained athlete shows a higher activity in oxidant enzymes, 3 or 4 times greater than that of a medium level athlete. The higher the web of capillaries per muscular fiber are, a higher percentage of fibers in slow motion, the higher the volume in maximum oxygen intake (VO2max the medium level athlete intakes 45 to 55 ml/kg./min and the international level athlete intakes over 60 ml/kg./min).

There is a consensus between the physical and biochemical adaptations that follows resistance training they should be that the increase in the energy necessities at the muscular cellular level. There for, the kind and the length of the force exerted with rest per series chance the relative necessities for every period of adaptation, in particular through the metabolism of the muscular cells. The subsequent adaptations that occur, at systematic and cellular levels, are particular characteristics in relation to the program of training.

Once the VO2max of the athlete is reached, the development will no longer be in the increase in amount and time of practice at sub maximum intensity. The development will then be related all to the elimination of the lactate (La).

The purpose of training with high intensity intervals is to cause the repetition of the physical system that will be used during specific exercises with the intent of increasing the extension of that activity. The difficulty that coaches face is that there are no training programs for highly trained athletes of high endurance.

The program planned for training should be based on the individual capacity and recuperation of each athlete. This capacity of recuperation can be modified everyday at every practice being that, there for, fundamentally always have in mind of the individual variances in capacity in response, to the loads of training and recuperation. You should always there for, consider the planning of the activities in training.

Therefor, so that the athlete with high endurance can reach the best development of resistance (aerobic capacity) will only be possible with training that involves series with high intensity.

Interpretive guide for testing aerobic and anaerobic capacities with examples

(Test of 400, 200, and 100 m style of the swimmer) 

The test, preferably, should be, administered after a block of training, observing the qualitative diagnostic of the aerobic and anaerobic capacities referring to a phase of training proposed by the coach.

It should be administered on a week of rest. With no interference of intense anaerobic stress

(Only after 72 hours). Will the athlete be rested.

The tests should also be done at the same time in the came pool as before in order to have comparative validity.

Order in which test should be administered:

  1. Fill out the chart of aerobic and anaerobic capacities.
  2. Take not of base pulse (take the pulse 3 times 60 sec each and take the average), stipulate the maximum pulse of the athlete (by age or other method) take the athletes pulse before the test (important to calculate the athletes VO2max in the test).
  3. A 400m swim is done preferably in free-style, or in the main style of the athlete (breast and back) depending on the athlete/coach’s preference. A butterfly style swimmer should take the test in free-style. A medley swimmer should also take it free-style or their best style. Important in the 400 m, depending on the intensity of the lactate in the athletes blood the test should be done in the style they would normally do the 400m series.
  4. The warm up should now make them apt to do the test.
  5. A 400 m swim (duration of 4.5 to 6 minutes) the duration must be long enough that the production and elimination of lactate reaches equal levels. The swim should be done at a moderate and constant speed during all four 100 m passages. The production of the lactate by the muscles will stop after the swim, this way the elimination will gradually decrease in the blood.
  6. The swim can measure the aerobic and anaerobic capacities of the athlete, there for, the test should always be don under anaerobic limits. Sprinters, because of the high production of lactate, should do the swim 50-60% of their maximum speed. The medium length swimmer should swim at a speed of about 60-70%, and the long distance swimmers should swim at a pace of about 80-90%.
  7. The elimination and production of the lactate should be at perfect dynamic balance and the lactate test should be taken right after the test; 1 minute after the end of the test.
  8. If the concentration of the lactate is higher at the third minute, is higher than at the first that means the swim was done in speeds above the anaerobic limits, there for, the results of the aerobic capacity can be false. (Usually happening in sprinters and medium length swimmers with the increase in pace at the last 100 m which is natural to them without even knowing.)
  9. In this case the test should be repeated by doing the following; the athlete will swim for 15 minutes at about 30-40%, the, a 5 to 10 minute rest until pulse and breathing return to normal then repeat the test once more following the steps listed before.
  10. Another possible cause the in error of the reading is if the lactate in the blood is found below 2.5 mmol/l. Two mechanisms that can be responsible are A – aerobic stimulation with the predomination of the metabolism being fat (% of oxidation in fat is above 20 %) prominently in long distance swimmers with a high aerobic capacity and a low or medium anaerobic capacity. B – Athletes with a depleted supply of glycolysis ( the lactate does not go up because the glucose is not running to pyruvic acid and vice versa causing a depletion of energy) also from lack of carbohydrates, which causes a lack of glycolysis occurring.
  11. In this case, it is important to diagnose the origin of the depletion of glucose.
  12. The test should be postponed until their diagnosis. In case “A, the test should be done at intensity to match their level of anaerobic capacity.
  13. Take not of time (in seconds), cycle of strokes every 50 m, pulse immediately 1 minute after. Collect lactate 3 minutes after via digital.
  14. The 200 m test style (in this case the best style of the swimmer) whose total stimulated time is maximum 3 minutes, which is not enough to reach the equilibrium of the lactate, serves mainly for 200m swimmers. Compare aerobic capacity (at 4mmol/l) with athletes of their style and international level. This test will fit the criteria given by the coach. Athletes that swim 200m, this test will be important when comparing with their final results. The proceedings are the same as those of the 400 m, except the percentage of speeds will be slightly higher.
  15. The 100 m test will be done at the swimmers best style and will be broken down in to two parts. The first part of the 100 m test should be done a t a moderate speed (between 4 and 6 mmol/l) with its length lasting no more than 2 minutes, not enough time to gain lactate equilibrium, this test serves to compare aerobic capacity (at 4 mmol/l) with athletes of their style to international athletes.

The proceedings are also the same as the 400m test. After an active resting period that follows the same as the 440 m test, administer the second part of the 100 m test pure speed (maximum stimulation).

In this case what is trying to be reached is the maximum production of lactate (anaerobic capacity). The time of stimulation to the maximum speed of the athlete. The athlete should be motivated to complete this portion of the test. Note time (in seconds) and cycle of strokes every 25/50 m. take pulse immediately 1,5,10, and 20 minutes after the test. Collect lactate 3, 5, and 7 minutes after test or until the highest value. It is suggested to also collect the lactate after 20 minutes of absolute rest.

The test of V4 calculation for 400m will yield the intensity of the swim for training for series of 400, 200, and 100 m with intervals of 10 and 30 seconds each. These series should, for the minimum, reach a total distance of 2400 m.


6 trials of 400 m = total 2400 m.

12 trials of 200 m = total of 2400 m.

24 trials of 100 m = total of 2400 m.

The form of which of which it is realized with the objective of bettering the condition of an athlete depending on the conditioning and characteristics of each swimmer.

We can cite that swimmers in a series of 6x 400 m with 30 seconds o rest after a constant speed to 3.5 mmol/l in one 400m test.

After the first repetition the lactate in the blood was 3.5 mmol/l. After the second and third repetitions the constant speed was equal, a drop in the lactate was then detected to an average of 2.7 mmol/l, where it remained for the rest of the tests.

What really happened? – After the first 3 repetitions the contribution of the aerobic metabolism, which requires a certain amount of time to reach its desired level of energy, was progressively increasing, gradually taking the job of the anaerobic lactate system. This reduces the production and elimination of lactate/pyruvic acid, and using it as fuel. Consequently less lactate being released into the blood stream. The concentration in the measure lactate will decline.


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Sprinters should choose the means of their aeorbic conditoning carefully. Long- low intensity swimming in a pool will only train your body to adapt to a low contractile speed, great longevity type energy system. Sprinters don’t need to swim forever. I would suggest stationary bike training to exercise aerobic energy systems. James Magnussen utilizes a stationary bike this way.

Bushan kumar

Lots of information on lactate testing. Thank you Coach Arilson.

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