I get quite a few questions from athletes regarding lactate threshold testing and if they should pay for this service at a lab or just do a field test outside. Let me address some of the confusion out there (as there is a lot of it!).
1. Lactate threshold as the name implies, is not really a "threshold" per se. The word threshold suggests that there is nothing above it. Rather, I have coined the term "lactate clearing efficiency", or LCE, to describe this term better. Why? Simply put, a lactate "threshold" test measures how efficient your body is at clearing lactate. You see, we are always producing lactate (it is a product of a metabolic cycle called glycolysis). Lactate isn't bad as it can be used for energy. However, above a certain intensity, and the build up of hydrogen ions actually begins to impair our performance.
Exercise is still possible above the lactate "threshold". Measuring the LCE provides us the point in time (as defined by heart rate, power, and/or pace) when our body begins to accumulate more than it can clear.
2. Once the LCE point is found, it's pretty easy to determine training zones. This is arguably the most accurate way to determine zone training. Sure, you can do some field testing but it is more difficult to control environmental conditions.
3. Here's where the real difference lies in lab (where blood is sampled every stage) vs. field testing, and one that many do not know. In a lab based test, yes, you are provided training zones but in my opinion, that is not the "a-ha" moment that you really need. More importantly, you can get a clear sense of the energy system that is weak or strong. For example, say a triathlete comes to visit me for a test and we learn that his aerobic energy system is a bit weak (as evident by the millimoles of lactate in his blood) but his anaerobic energy system is in full swing and ready to engage.
With this data, I can provide this information to the athlete and his coach, if he has one, to provide a better picture of where his training focus should be depending on the distances and his preparation timeline. Perhaps he is training for Sprint and Olympic distance triathlons and the season is 8-12 weeks away. This is a great place for him to be since his anaerobic energy system is so well prepped. However, if he was gearing up for an Ironman distance and only had 8-12 weeks left to train, it would be obvious that the energy system in most need would be aerobic.
In summary, it doesn't matter what name we give this testing. The important take away is that you can get much more data than just training zones from a properly executed lactate threshold/clearing efficiency test.
If I left you a bit more confused, feel free to reach out via email. I'd love to hear from you!