i have no idea what the possible mechanism for this could be, ie intense workout making opiate high better for that day... but i could speculate?
a. natural endorphin levels would be increased after workout having synergistic effects with opiates.
b. upregulation of opiate receptors possibly? i have seen examples of upregulation of specific receptors by exercise (namely insulin receptors) but i doubt it
im not sure about exercises effects on enzymes though... by products of exercise could be co-factors to the mentioned enzymes and possibly make them function better... but i doubt it! that enzyme is responsible for a shitload of things, imagine all the stuff that would start happening everytime we went for a run??
ok just outta curiosity's sake i searched through some literature and found that regular exercise actually attenuates the effects of opiate drugs. they mentioned a cross tolerance between endorphins and opiates (both working on same receptors).
so it wouldn't be hard to imagine leftover endorphins in your system after a long workout (nine hours did he say?) plus extra opiates = greater high.
but, drawback is a quicker/bigger tolerance..!
and hey Kompelz, i remember ya