Kristina, I agree completely with Mike.  Less is more.  I also do high intensity weight training but limit it to about 10 exercises, one set each, twice a week.  I found myself getting colds and having general lack of energy when I've tried to add cardio to that.  As long as you're not resting between sets, the weight training puts more than enough strain on the cardiovascular system.  Email me if you'd like to discuss more.
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