Pipes

Ok, so this might (meaning probably is) a dumb question, just a warning. I smoke a pipe with my buddies about once a week, usually less. I know all the negitive effects that tobacco has on the system (decreased o2 delivery etc,), I just wanted input as to how I should alter my training after I smoke. Some times my buddies want to go out, I have a workout that day, so what should be different, if anything?
thanks
-K