Interpreting Your Results

The blood lactate response to exercise has been described using a variety of terms, including lactate threshold, maximal steady state, anaerobic threshold, aerobic threshold, and onset of blood lactate accumulation. In current literature, authors often interchange the terms which leads to confusion on the part of the athlete. Thus, the first important step is to provide some common definitions used in current research to describe the blood lactate response to exercise:

• Lactate Threshold: The highest speed (running) or power output (bicycling) that can be maintained during exercise before an elevation in blood lactate is observed. This occurs just before the curvilinear increase in blood lactate is observed when blood lactate is plotted vs. speed/power from exercise tests in which subjects perform a series of increasing bouts of exercise intensities at work increments of 3-5 minutes.
• Anaerobic Threshold: The point on the lactate curve where there is an exponential shift in blood lactate levels. Most commonly occurs around 4 mmol/L of lactate along with an increase of > 1 mmol/L from the previous workload.

A typical lactate test pattern shows a low plateau of 1.5-2.5 mmol/L lactate early on (lactate threshold), slowly increasing to ~4.0 mmol/L (anaerobic threshold), and then taking off to 5-6 mmol at the next stage. Another profile is the athlete who maintains low lactate levels (2.5mmol) up to pretty high workloads (a high lactate threshold), and then at the next stage the lactate level jumps to high 4’s or even 5’s. This indicates their lactate threshold HR is just slightly below their anaerobic threshold HR, with little transition area in between. Such an athlete won’t be able to run/bike for long above their aerobic or anaerobic thresholds because they are not yet trained for that. Applying the “overload” principle, they have overloaded on duration, not intensity, thus causing muscle adaptations that foster efficient aerobic energy production. A third profile is seen in novice athletes where the lactate pattern shows a plateau at a higher level of 2.5-3.5 mmol/L when compared to more seasoned athlete with plateau’s around 1.5-2.5 mmol/L. This is due to a less developed aerobic system.

Your lactate threshold typically occurs around 1.5-2.5 mmol/L while most anaerobic threshold levels are seen at ~4 or even 5 mmol/L. Your lactate readings at VO2 Max will commonly be between 5-10 mmol. This value depends on your training history, your present training status and where you are in the season, and your experience in the sport being tested. Anaerobic capacity workouts typically lead to higher lactate levels of 7-8 mmol for some athletes to as much as 14-16 mmol for the serious speed demon. Since sprint triathletes perform more high intensity training than Ironman triathletes, their lactate readings should be on the higher end while Ironman racers will primarily be performing at paces that normally elicit a lactate level of 2-3 mmol or less.

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