I'm trying to get fit as my cardio vascular system leaves a lot to be desired! I have joined a boxing club so that I can have someone shout at me to make me move. However I have a few questions...

I nearly fainted last night I worked so hard - how can I stop this from happening? I ate an oat, hazelnut and chocolate bar before training because I thought it would be a good combo of slow release and instantaneous sugar - but it didn't really work.
So what should I eat before training?

Also how often should I go to start with (they train mon, tues, wen) I don't want to get sick like what usually happens when I start trying to get fit, but I want to do enough to see an effect.

Oh and I'm female an in my early twenties if that's relavent.

Thanks for any advice! :p

Hmm... I need to temper my response here or else I'll be all over the map.

The first thing you need to look at is your personal goal. It sounds like general cardio conditioning is your goal, so let's examine that.

There are 3 basic pathways that the body accesses for energy:

Aerobic, Glycolytic, Anaerobic

Boxing and Football generally fall into the glycolytic pathway of muscular energetics, so we'll focus on that for now, and where my brain went when trying to find an answer to your question.

Since I assume you're not a beginner, but you ARE deconditioned at this time, I would personally stay away from a Mon-Tues-Wed schedule. Not only will it tax your body before it's ready, you're also giving yourself 4 days off. That's a bit too long for my liking.

Instead, try Mon & Wed at the boxing gym and then work out on your own on Friday. Maybe stick with the aerobic or anaerobic pathway on Friday just for a change of pace, but at least spread out your training.

Try that for a month, and then shake things up a bit with the schedule.

If getting sick is a common issue, then the last thing you want to do is overtax your body and cause your immune system to weaken. The best way to do that and still generate results is through periodization and proper nutrition.

Everything else is luck and hoping that the dude who sneezes next to you in the elevator doesn't get you sick, too.