Part I: Lactate – What is Lactate?

Fun with Lactate!
Fun with Lactate!

Your Lactate Threshold (“LT”) is the single biggest determinant of endurance race performance (Kravitz & Dalleck). In addition, it is the most reliable way to track your progress. Beginner triathletes come into the sport from different backgrounds and may respond differently to various types of training. The best way to know whether it’s working is by testing it “in the lab”. “The lab” represents a consistent atmosphere that is repeatable and controls for variables such as wind, hills, stops lights and heat. The test will tell you which energy systems you need to work on and can play a major role in determining your next training cycle. Testing this directly from your blood is testing it at its source.

You reap the benefit of this in training, since it allows you to train efficiently and effectively. Now that you know your LT, your “Threshold workouts” will be perfectly tailored so you train just below it, which allows you to adapt and increase it. You can then tailor your anaerobic workouts (above threshold) to teach your body to learn how to flush out the “acid” (we’ll define acid in a little bit) effectively so you can recover quicker and are ready for the next hard effort quicker. Finally, your recovery workouts will be exactly that, recovery. There is no more guesswork, you have your zones.

An example on the opposite side of the spectrum is a common challenge that new triathletes face when coming in from other higher intensity sports. They train with an ‘all or nothing’ mindset. In other words, they train too hard too often. These athletes may be very physically fit but produce too much “acid”. In these cases, once identified, it may be beneficial to set a training program where they will get better by keeping their workouts aerobic and detraining their anaerobic system! Yep, I said it! Detrain the anaerobic system. Before I explain why, it is useful to know how your anaerobic system works:

Science Alert (although this is somewhat simplified, skip ahead if you aren’t into the technical stuff): Upon digestion, carbohydrates and sugars turn into glycogen. Glycogen fuels the anaerobic system. As it releases energy, Pyruvate fuels the aerobic system while lactate and positively charged Hydrogen ions (H+) are released into the blood stream. Blood is responsible for carrying oxygen and other nutrients to your muscles. The harder your effort, the more lactate and H+ accumulates in your blood and muscles. Eventually, you are going to reach a point where you cannot flush the lactate and H+ from your muscles faster than you are producing them. That is your Lactate Threshold (“LT”).

Energy and lactate production system.
Image thanks to Jerry Kosgrove at

Now that we have covered that, there is an important distinction to be made between Lactate, Lactic Acid and the H+ ion. Although lactate is released into the blood at the same time as H+, it is NOT lactate or Lactic Acid that causes the burn in your muscles. It is the H+ ion that is the “acid” mentioned above. Lactic Acid is actually a fuel source. It easily travels through cell membranes to the liver and converts back to glucose for more anaerobic fuel. The reason why we measure lactate and not H+ is that this is much easier to do. They are directly correlated; they are produced at the same time and lactate is actually the buffer that helps deliver H+.  It is common to hear people say that lactic acid causes the burn. Unfortunately, this is inaccurate. If it were true, it would certainly be easier to explain, but ultimately for us athletes (ie, nonscientists), it means the same thing, just replace lactic acid with “positively charged Hydrogen ions”.

Speaking of Hydrogen, did you know that pH stands for the power of Hydrogen? So when you flood your muscles with positively charged Hydrogen ions, you are making them more acidic. In other words, your pH balance gets more acidic. Per WikiPedia: “in chemistry, pH is a measure of the acidity or basicity of an aqueous solution. Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline. Pure water [is completely balanced and] has a pH very close to 7.” The pH range goes from of 0 to 14, with 0 being very acidic and 14 being very basic (alkaline). The pH balance of human blood usually stays around 7.365. Even with an extremely hard workout, our pH does not go very far outside of the 7 range. Thankfully, we are limited on how acidic we can get. Lactate is the base (alkaline) and lactic acid is the acid. Although hard exercise increases our acidity, consuming alkaline food while we are exercising will not have an effect on our immediate recovery. But consuming alkaline food as a regular part of our diet is very highly advised. There is some debate about whether it is the alkaline that helps or whether alkaline foods also tend to be more nutrient dense that is what helps. Regardless, try to limit highly acidic foods, like processed foods (stripped of nutrients), or wheat and sugar that do not have many (or any) nutrients. Fruits and veggies, on the other hand, are high in alkaline and coincidentally have a lot of nutrients. So although your blood remains pretty stable (slightly alkaline), avoiding acidosis is important to keep inflammation under control and eating a nutrient dense diet is extremely important to fuel your workouts.

Coming up in Part II, how this all relates to better performance.

Special thanks to Jerry Kosgrove and the plethora of information at

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