If I were you, I wouldn't focus on sweating. You could be sweating just standing outside and you wouldn't be doing any cardio.
You need to buy a heart rate monitor and focus on keeping your heart rate between the higher and lower limits during your cardio. To figure it out, do this:
Subtract your age from 220. That will give you you maximum heart rate.
To get your higher limit, multiply your maximum heart rate by 0.9.
To get your lower limit, multiply your maximum heart rate by 0.6.
Your heart rate should be between your higher and lower limits at all times during the cardio. Avoid going over the higher limit.
I don't chase, I replace.