What is Anaerobic Threshold

The anaerobic threshold is the maximum intensity at which lactate production equals lactate consumption.

At certain intensity lactate concentration will indeed stabilize at its maximum level (maximum lactate steady state).

Above the anaerobic threshold pace an athlete will produce more lactate than what he/she can use in combustion and due to an increase in H+ ions ph levels of the blood will decrease making it more acidic.  An intensity above anaerobic threshold can therefore not be maintained for a long period of time.

By incorporating workouts at (or above anearobic threshold - see VO2Max training) a runner may be able to increase its anaerobic threshold and/or increase the duration he/she can maintain this intensity.