Lactate threshold

Lactate inflection point (LIP) is the <a href="/facts/Exercise/egYQjt8A">exercise</a> intensity at which the blood concentration of lactate and/or <a href="/facts/Lactic_acid/BsVRFx7s">lactic acid</a> begins to increase rapidly. It is often expressed as 85% of maximum heart rate or 75% of maximum oxygen intake. When exercising at or below the lactate threshold, any lactate produced by the <a href="/facts/Muscle/dmxrL8pH">muscles</a> is removed by the body without it building up.
The onset of blood lactate accumulation (OBLA) is often confused with the lactate threshold. With an exercise intensity higher than the threshold the lactate production exceeds the rate at which it can be broken down. The blood lactate concentration will show an increase equal to 4.0 mM; it then accumulates in the muscle and then moves to the bloodstream.
Regular endurance exercise leads to adaptations in skeletal muscle which raises the threshold at which lactate levels will rise. This is mediated via activation of the protein receptor <a href="/facts/PGC-1%CE%B1/dEgNkMAx">PGC-1α</a>, which alters the isoenzyme composition of the <a href="/facts/Lactate_dehydrogenase/FGuLGcXe">lactate dehydrogenase</a> (LDH) complex and decreases the activity of lactate dehydrogenase A (LDHA), while increasing the activity of lactate dehydrogenase B (LDHB).

Lactate threshold open-in-new

Lactate threshold