op io id ▁re cept ors , ▁in ▁turn ▁producing ▁eu ph oria ▁and ▁pain ▁relief . ▁A ▁meta - anal yt ic ▁review ▁found ▁that ▁exercise ▁significantly ▁increases ▁the ▁secret ion ▁of ▁ ▁and ▁that ▁this ▁secret ion ▁is ▁correl ated ▁with ▁improved ▁m ood ▁states . ▁Mod er ate ▁intensity ▁exercise ▁produces ▁the ▁greatest ▁increase ▁in ▁ ▁synth esis , ▁while ▁higher ▁and ▁lower ▁intensity ▁forms ▁of ▁exercise ▁are ▁associated ▁with ▁smaller ▁increases ▁in ▁ ▁synth esis . ▁A ▁review ▁on ▁ ▁and ▁exercise ▁noted ▁that ▁an ▁individual ' s ▁m ood ▁impro ves ▁for ▁the ▁remainder ▁of ▁the ▁day ▁following ▁physical ▁exercise ▁and ▁that ▁one ' s ▁m ood ▁is ▁posit ively ▁correl ated ▁with ▁overall ▁daily ▁physical ▁activity ▁level . ▁ ▁An and am ide ▁ ▁An and am ide ▁is ▁an ▁end ogen ous ▁can nab ino id ▁and ▁retro grade ▁ne uro trans mit ter ▁that ▁bind s ▁to ▁can nab ino id ▁re cept ors ▁( prim arily ▁C B 1 ), ▁in ▁turn ▁producing ▁eu ph oria . ▁It ▁has ▁been ▁shown ▁that ▁aer ob ic ▁exercise ▁causes ▁an ▁increase ▁in ▁pl asma ▁an and am ide ▁levels , ▁where ▁the ▁magnitude ▁of ▁this ▁increase ▁is ▁highest ▁at ▁moder ate ▁exercise ▁intensity ▁( i . e ., ▁exer cis ing ▁at ▁~ ⁠ 7 0 ⁠ – ⁠ 8 0 ⁠ % ▁maximum ▁heart ▁rate ). ▁In cre ases ▁in ▁pl asma ▁an and am ide ▁levels ▁are ▁associated ▁with ▁ps y cho active ▁effects