Lactate Threshold Test - What is it and What can it tell you?

A high VO 2 max is a prerequisite for successful endurance performance. However, the ability to maintain high percentages of this maximal level without the excessive generation of metabolic by-products such as lactic acid is also very important and is often a better predictor of performance.

Lactic acid production increases when the body’s ability to control the production of the by-product is exceeded. As the intensity of the exercise increases so will the levels of lactic acid in the blood forcing the exercise intensity to be lowered or ceased altogether. Lactic acid levels can easily be measured by taking a finger prick blood sample.

The rise in lactic acid levels usually follows two thresholds. The first threshold occurs when the lactic acid levels start to rise up from baseline levels. It is at this point where endurance base work, such as long rides or runs, would take place. This point is strongly related to performance in prolonged endurance events. The second threshold occurs when you are working at an intensity whereby there is a dramatic increase in lactic acid within the blood. This point has often been termed the “anaerobic threshold”. Performing interval bouts around this point will not only help your body get used to high levels of lactic acid it will also aid its ability to “recycle” it and use for energy. Interval bouts need to be long enough (3-10 minutes) to build up the lactic acid levels and recovery periods of sufficient length to recover before the next work bout. This is often an area that is neglected due to the commitment required to exercise at these intensities. This area is related to events of shorter duration (ie 10km run 10mile cycle TT).

By correlating the deflection points with your heart rate allows precise bandings in heart rate to allow you to monitor the intensity of your session.

Quite often the heart rate at these particular thresholds remains constant, what increases is the speed/power you can maintain at these heart rates.

The graph above illustrates the two thresholds and also indicates the effects of training on the lactate curve. The blue line illustrates pre-training with the red post-training. The post-training curve has moved to the right indicating that the athlete can now exercise at a higher work rate at the different thresholds. By regularly monitoring the lactate curve (i.e. every 3-4 months), training intensities can be altered to reflect these improvements in performance.