The Body In Swimming: The Dogma Of Lactic Acid

by SwimSwam 48

June 20th, 2017 Lifestyle

Courtesy Stuart Dustan

While watching the recent Scottish National Open Championships 2014, held at Tolcross, I couldn’t help but notice the continued use of ‘lactic acid’ testing inflicted on a large number of swimmers immediately after their race. The procedure, used in most national and international competitions, involves a small extraction of blood from, usually, the athlete’s ear. The concentration of the ‘acid’ present in the blood is then calculated using the testing equipment. The results are used to show the ‘anaerobic capacity’ of the swimmer as the acid build up indicates the body’s use of muscles in the absence of oxygen. Well, that’s the belief anyway.

The truth is, there is an enormous amount of misunderstanding and gross overestimation surrounding the area of lactic acid, and it’s testing – starting with the name! Those who refer to lactic acid as the chemical present in your bloodstream have already blundered, it is, in fact, the substance ‘lactate’ which is present in your blood and which is tested for in ‘lactic acid concentration tests’ described above. Lactic acid ‘splits’ into lactate and hydrogen which then enters the blood. The misconceptions go far beyond this, however.

Lactate testing is used to determine the anaerobic capacity of an athlete, as it is believed that increases in lactate correlate with muscles which are working without oxygen. Thus, the higher the levels, the greater the anaerobic capacity of an athlete. Well, the first point to highlight is that lactic acid is not only produced in the working muscles – the liver is a major contributor as well as other tissues such as the skin and intestines. Brooks, et al. (1992), stated, “Lactate measures cannot be inferred to indicate only exercise production”. Another point to note is lactate production is also observed in both fully aerobic tissue – such as the heart, and oxygenated muscles. Lactate production in the muscles merely provides information that an athlete has ‘worked’ at a particular intensity – full stop.

Lactate – the root of all evil…or is it?

Often heard from the mouths of swimmers and other beings who participate in sport are sentences such as, “Ow! My muscles are rather sore today, I must have built up a lot of acid,” or, “Thanks to that darn lactic acid, I can barely move” (or something to that effect). An overwhelming number of coaches will reinforce this blame; however, lactic acid/lactate is in fact, not guilty.

It is a common belief that fatigue, muscle soreness and stiffness are caused by a high accumulation of lactate in the blood which has not cleared, or that the lactate has somehow ‘acidified’ the blood. With regards to fatigue, lactate in the blood does completely the opposite to what is often thought. Lactate prevents the effects of fatigue and is even a useful source of energy in the body. Lactate is converted in two ways, either, into glucose – which will be stored in the liver, or as carbon dioxide and water. The latter two both remove hydrogen (ions) from the blood – hydrogen is a contributor to acidosis and, as a result, fatigue can occur (other factors also contribute). Thus, the presence of lactate can help offset the effects of fatigue in an athlete. Lactate can also remain in the cells it has been produced and be used as fuel. Miller, B. (2002), has shown that lactate can be the preferred source of energy over glucose in cells.

With regards to muscle soreness and that stiff feeling felt by many, this is the result of muscle cell damage due to a level of intensity not usually endured by the athlete. It can also occur when the muscle fibres have been used in an unfamiliar way – likely with a heavier than normal load.

A.T. – Anaerobic threshold or a total waste of time

If you are a swimming coach or athlete, it is highly likely you’ve heard of, or swum an anaerobic threshold set; or indeed you may have written one up for your swimmers. Firstly, what is the anaerobic threshold? The standard explanation is, as the swimmer’s velocity increases, a point or threshold is reached whereby the muscles no longer have a sufficient oxygen supply and the body’s supplies, which can provide energy in the absence of oxygen, are employed – this leads to a spike in lactate. A simpler explanation of the threshold is the point at which the body can no longer equal lactate production with lactate removal, thus, causing an accumulation of lactate.

If you’ve been following the format of this post, you’ll know what is coming next.

The above is an erroneous explanation of what takes place. The muscles, to begin with, do not become anaerobic for any more than a few seconds (otherwise, you would die). The accumulation of lactate is a result of factors such as glycolytic rate and other metabolic ‘coping’ responses – rather than as a result of anaerobic conditions. Also, the use of the word threshold is inappropriate. The process is gradual; it doesn’t suddenly spike as suggested. In training, anaerobic threshold training is conducted so that a swimmer will be able to maintain, for longer, the period in which the body can balance lactate production with its removal. I have already covered why there is no justification for this type of training. Furthermore, even if the emphasis was moved to using anaerobic threshold training to directly improve fitness (VO2 max) as it tends to be faster than normal aerobic paces, we know that intensities above “anaerobic threshold” are only effective in improving VO2 max. The latter has been shown to have very little to do with race performances. In short, anaerobic threshold training is a waste of time!

In closing, huge amounts of dogma exist in the world of lactate, and it’s testing. The best an analysis of a swimmer’s anaerobic threshold (or lactate threshold) can achieve is, to inform the athlete, or whoever is concerned, that their physiology has ‘changed’. This is perhaps useful when observing someone who wishes to move from an untrained state to one which is trained. Thereafter, a change (caused by training) may be evident, but what has that got to do with swimming performances? Nothing. Certainly not for those swimming in-pool competitive events. Hopefully, this article will prevent a couple of coaches from straying toward an erroneous belief-based practice and can now better spend their time on evidence-based training. At the very least I hope this will stop just one coach/swimmer/parent from explaining a ‘bad’ performance was on account of lactate, or worse – lactic acid!

About Stuart Dustan

Residing in Scotland, Stuart has been coaching for numerous years and has belonged to a variety of clubs across the country. He started his coaching career with Forres Bluefins ASC moving on to Perth City SC whereby he worked alongside one of the most experienced coaches in Scottish Swimming, assisting with the development of a number of successful swimmers including an Olympic medal-winner. Stuart now spends his time coaching within a large swimming club in Dundee (Dundee City Aquatics) and, he is also a long-term member of the executive training team within one of the only specialist sprint clubs in the UK – Free Style SC. Free Style utilises an evidence-based and scientific approach to training. Stuart has experience as a researcher in Medical Science and he utilises this experience to critically review scientific literature related to athlete performance. He can often be found on Twitter engaging in respectful, yet critical debates with other coaches on swimming science (@SwimCoachStu).

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Great piece, I hope this stirs a lot of debate. I suggest that after reading and digesting this article, go to the June 19 piece on Elizabeth Beisel’s 4:40 IM (Beisel Has Huge Swimming Base), and put your critical thinking cap on.


Maybe part of the reason so many coaches resist change is because of the arrogant tone with which it is presented. It’s also not as cut and dried as you make it sound. I don’t have time for a long post right now, but maybe later. We’ve been down this road before…


dddoooo it!!


Lactate testing can be used for other reasons than to estimate/determine anaerobic capacity. In fact, I’ve never seen it used to try to quantify anaerobic capacity, as that term is ambiguous at best. I have seen it used to determine Anaerobic Threshold, though, which does show a “hockey-stick” peak when the rate of production exceeds the rate of removal, in a well designed test set. But after years of study and implementation, the foremost authority on lactate testing in swimming (Maglischo) admitted that testing isn’t critical to getting it right. He is a true scientist, and admitted that you can get close enough with a ballpark estimate based on perceived effort level. Ironically, he never made a single superlative statement… Read more »

Curious Jorge

Cynic: Well put. I’m an Ernie Maglischo guy myself, and he recommended in a podcast a book by Dr. Jan Albrecht… As he goes deeper into the processes you describe, specifically the rate of lactate removal and the use of lactate testing.

I actually posted a response to the author also, but I think SwimSwam deemed it not appropriate, so kudos to you for articulating what I wanted to say without sounding like a troll (me).


Jorge, I’ve only met him in passing at clinics where he spoke and don’t know him well, but I competed against his teams and know many people that are close to him. By my estimation he is a smart, humble man who spent his career trying to get better at his craft, and I think his results tell the tale. If you read his Swimming Faster, Even Faster, Fastest books, you can see the evolution of his philosophy. It seems he has no ego what so ever, especially as he delivered his mea culpa with regard to lift vs drag propulsion and also with the need to pinpoint training paces via lactate testing. I think he has advanced the sport… Read more »

Stuart Dustan

Thank you for your extensive response ‘cynic’. Again, I would claim based on literature reviews I have conducted that, the only thing a lactate test can do is inform the tester that lactate was produced – it cannot indicate where. To deal with the specific points you make in a single way, can you direct me to the evidence which indicates that anaerobic threshold is a good indicator of performance or, that it can relate to improvements in competitive swimming performance in any way? I have conducted such a review and I am still waiting. It’s interesting that you keep referring to Rushall, yet I haven’t mentioned him. Why don’t you provide me with a rebuttal on the points and… Read more »

Lactate Lover


I’m with Cynic, as we both subscribe to the evidence or lack thereof according to Maglischo. Are you familiar with his work? Anyways, you say, “you should change your mind in light of new and superior evidence.”

My question is, how is the evidence you have come across more superior than Maglischo’s?

Stuart Dustan

I am very familiar of Maglischo and I used a lot of his work as my foundation to understanding how the body reacts within swim training and races. However, I think his understanding of energy systems is limited. PLease see below for a link to a comprehensive paper regarding the proposed understanding of energy system usage in swimming. I am critical of a number of points the author makes; however, I agree with the major points:

I’m afraid it is a long read:

Happy reading.


And there it is, “The Rushall Cult Manifesto.” I’ve never seen a less objective piece of “Science”. There is absolutely some good stuff in there, but if you cannot see the lack of objectivity throughout, then you are a true believer. Can I get an AMEN!


Some of these things are difficult to prove…yet it doesn’t mean they aren’t true. At some point, when there is not evidence, you have to use common sense. Maybe swimming a 100 freestyle in competition causes the liver to produce huge amounts of lactate…but I doubt that is the reason for the dramatic increase in lactate that results. I think it is reasonable to conclude that the increase in lactate as compared to pre-race levels is due to some metabolic process. Likewise if a 100 freestyle is performed at less than race pace, and we don’t see a similar delta, I think it is reasonable to conclude that the result is due to some other metabolic process or response. I… Read more »

Stuart Dustan

Thanks again for your response, I think I have laid out my disagreements fairly extensively. I shall leave the readers to decide which view to support. “Evidence-based coaching is great, except in situations where there is no evidence.” Yes, but that is why it is known as ‘evidence-based’. Failing a supply of reliable and significant evidence on a swimming related issue, one should apply scientific rationale and logic. Of course, the role of a Sports Scientist, Scientist or, Coach, is to take the results of a body of evidence and, apply it in a way which is possible in a training pool. Indeed, in the case of lactate testing, the less than significant and weak studies on the latter is… Read more »


Thank you for articles like this. The vast majority coaches are so under-qualified to be making ‘scientific’ recommendations especially in the areas of physiology, psychology, and even physics!

Curious Jorge

Dr Ernie Maglischo, Dr Jan Albrecht, Dr Dave Salo all use or advocate some form of Anaerobic Threshold/capacity training. Underqualified?

Andrew Webber

There’s two logical fallacies there, the argument from authority, and the argument from antiquity.

Stuart Dustan

Hear, hear Andrew! You took the words out of my mouth.


USRPT and “evidence based training” is completely based on a logical fallacy: argumentum ad ignorantiam-assuming that a claim is true because it has not been or cannot be proven false, or vice versa.

Stuart Dustan

Thank you Marc. I think the ignorance surrounding swimming physiology, psychology and other elements of swim science is a failing of swimming organisations and, those who create the coach education programmes as opposed to the fault of the coaches themselves.

Curious Jorge

I’ll speak for myself, as a coach here in California… Marc says, “vast majority coaches are so under-qualified to be making ‘scientific’ recommendations especially in the areas of physiology, psychology, and even physics!” I personally love the work of Dave Salo, Jon Urbanchek, Ernie Maglischo and most recently what Bruce Gemmel has been able to accomplish with Katie Ledecky. Anyways, I don’t believe any of the coaches above are underqualified, with Dave Salo currently coaching with a background in Exercise Science and Ernie Maglischo working exclusively on the science of swimming. All these guys do some form of AT training… Katie Ledecky lived in the AT and above zones when she trained leading up to London and Rio. With that… Read more »

Stuart Dustan

Curious Jorge, I would refer you to Andrew’s post.

“I’ve seen on the deck around here is many of the successful coaches are following in the footsteps of the giants in our sport, the ones who have done the research, practice it and are seeing success.” I wonder how may ‘failures’ they had or, how many athletes they lost to get to those successes?