The term Lactate threshold it is confused many times by most people, including most physiologist. There are many theories like the increase of 1 mmol above baseline or the blood concentration of 4mmol/L, also called OBLA (Onset of blood lactate accumulation). However, the body doesn´t have a "breakpoint" at which starts a lactate threshold. You can ride, eg, for 45 min at a blood lactate concentration of 6mmol/L but cannot do it for 2h. however (and again it is just an example) you can ride for 2 hours at a blood lactate concentration of 2.5 mmol/L but cannot sustain it for 5 hours....and etcetera, so when we talk a bout a "lactate threshold" what do we mean?; LT for 45t min?, or LT for 2h? or LT for 3h?....<br />Bottom line is the exercise intensity at which your muscle starts accumulating lactate and acidosis starts to increse, since your muscle cannot clear it out and builds up. Whatever the grade of lactate accumulation, there is always a "steady state" of lactate accumulation and this steady steate is sustainable overtime depending on the lactate accumulation. This means that we can reach a steady state of 5-7 mmol/L over 45-50 min but after that due to the incresed glucolitic flux the lactate concentration will build up more and power won´t be able to be sustained. Also we can ride at a "steady state" of , e.g., 2.5 mmol/L for 2.5 hours but after that the muscle won´t be able to keep up with that steady state and less lactate will be oxidated and it will build up more and that power won´t be able to be sustained more. It sounds a litle complicated and I don´t know If I am explaining it very well. ???. It is also important to know that not eveyone´s muscle metabolism is the same. The same blood lactate concentration is not the same for most of the people as most testers think. That is, at a 4mmol of lactate I can do a moderate workout but someone else can be doing a very hard exercise. So we cannnot just go by absolute blood lactate numbers. We have to measure what´s our individual exercise intensity at which we start to build up lactate and identify specially 2 exercise intensities for that: one at "moderate" exercise intensity, which would represent the amount of time we can sustain at that moderate intensity, generally hours and and the other the exercise intensity at the one we start building up much more lactate, This last intensity will be valid for TT´s and climbing.<br /><br />For this, it takes cualified and experienced person as well as an adeccuate protocol.