entially . ▁It ▁is ▁often ▁expressed ▁as ▁ 8 5 % ▁of ▁maximum ▁heart ▁rate ▁or ▁ 7 5 % ▁of ▁maximum ▁o xygen ▁int ake . ▁When ▁exer cis ing ▁at ▁or ▁below ▁the ▁la ct ate ▁threshold , ▁any ▁la ct ate ▁produced ▁by ▁the ▁mus cles ▁is ▁removed ▁by ▁the ▁body ▁without ▁it ▁building ▁up . ▁ ▁The ▁on set ▁of ▁blood ▁la ct ate ▁accum ulation ▁( OB LA ) ▁is ▁often ▁confused ▁with ▁the ▁la ct ate ▁threshold . ▁With ▁an ▁exercise ▁intensity ▁higher ▁than ▁the ▁threshold ▁the ▁la ct ate ▁production ▁exceed s ▁the ▁rate ▁at ▁which ▁it ▁can ▁be ▁broken ▁down . ▁The ▁blood ▁la ct ate ▁concentration ▁will ▁show ▁an ▁increase ▁equal ▁to ▁ 4 . 0 m M ; ▁it ▁then ▁accum ul ates ▁in ▁the ▁mus cle ▁and ▁then ▁moves ▁to ▁the ▁blood stream . ▁ ▁Reg ular ▁end urance ▁exercise ▁leads ▁to ▁adapt ations ▁in ▁ske let al ▁mus cle ▁which ▁ra ises ▁the ▁threshold ▁at ▁which ▁la ct ate ▁levels ▁will ▁rise . ▁This ▁is ▁medi ated ▁via ▁activation ▁of ▁P GC - 1 α , ▁which ▁al ters ▁the ▁is o enz yme ▁composition ▁of ▁the ▁L D H ▁complex ▁and ▁decre ases ▁the ▁activity ▁of ▁the ▁la ct ate ▁generating ▁en zym e ▁L D HA , ▁while ▁increasing ▁the ▁activity ▁of ▁the ▁la ct ate ▁met abol izing ▁en zym e ▁L D H B . ▁ ▁Training ▁types ▁ ▁The ▁la ct ate ▁threshold ▁is ▁a ▁useful