Not saying to smoke (talking about chewing the nicotine gum) because of the carbon monoxide/dioxied and cancer risk but I've heard of Nicotine's benifits in weight lifting.....here's what I found on a Drug reference:

-Two types of central nervous system effects are believed to be the basis of nicotines positively reinforcing properties

-administration of nicotine activates neurohormonal pathways, releasing acetylcholine, norepinephrine, dopamine, serotonin, vasopressin, beta-endorphin, growth hormone, and ACTH.

then again, the bad things we don't want. vaso constirction could be countered by NO2??

-The cardiovascular effects of nicotine include peripheral vasoconstriction, tachycardia, and elevated blood pressure.

-nicotine can increase circulating cortisol (not too great) and catecholamines (that's a good thing)