Catherine
i have been back at gym from 6 wks - i do about 3 classes a week inc reasonably intense cardio and weights - i have not had any BF or supply issues.
I have heard some bubs dont like to feed when yuo are sweaty - Noah doesnt seem to mindif i wipe myself down well and feed him (I guess he is such a guzzlerhe isnt too fussy LOL) but to avoid this bc i think it is a bit yukky i feed him just prior to the exercise so he can wait for me to come home and shower before his next feed.
i also swimand have heard the same thing wrt the smell of chlorine so i do this before a swim as well and have a good shower before i feed.
enjoy your workout!!

BEWARE i was shocked how UNFIT i was/am - and i did exercise through my preg!!!