A Lactate Threshold test identifies blood lactate transition thresholds which can be used to develop athlete training zones. These refer to the intensity you train at which can be given as a running speed, power output or heart rate. These thresholds are good predictors of endurance performance and are sensitive to training.
The test involves 3 minute exercise stages that are easy to begin with but gradually get harder up to a high intensity level. Heart rate (from a heart rate monitor) and blood lactate (from a finger or ear prick) are measured at the end of each stage. The test will last approximately 30-40 minutes. Two thresholds can be identified during this test - a report will be produced for you that will identify the thresholds and these will be used to set your training zones.
The first threshold occurs at the exercise intensity at which blood lactate begins to rise above resting levels, termed Lactate Threshold (LT). It marks the shift from purely aerobic (low intensity) exercise to exercise that requires some anaerobic energy contribution (moderate intensity) that produces lactic acid. Training intensity at or below LT is relatively low and one should be able to maintain it for a prolonged period of time (hours).
The second threshold occurs at a higher intensity than LT and represents the highest intensity (power output or running speed) that one can maintain for 30 minutes or so. At intensities above this, lactic acid would accumulate quickly to levels that would limit your ability to continue exercising because of fatigue.