Oh yeah BO's all part of the experience! I take a kickboxing class which is ADVANCED and full of MEN who STINK PHOOOOOEEEEEEEE!

But it wouldn't feel so tough if it didn't smell!
Anyway.... I have found a WONDERFUL deoderant, Mitchum, I don't know if you guys have it in the States, the packaging looks fairly American, so maybe you do. So this Mitchum is AMA-ZING I can run through a kickboxing class without sweating under my 'pits once this is on! The chest, back, waist, shins, hands are another matter...
Don't they have showers at your gym? Maybe you could take a shower straight after your workout to stop you stinking up the rest of the day? I doubt anyone will notice when you're actually IN the gym, they'll all be too busy smelling their own B.O.!