Based from my experience, too much exercise will increase heart rate, like it will continue to pump. I am not sure if the experience is the same as others, but from my experience, my heart beat faster and I was too tired. I exercised for more than an hour. I mixed my cardio exercise with dancing and I really enjoyed it. After that, it decreased my energy and I was too tired, getting near of collapsing. I am glad that I exercised inside my room.
Too much is when you do cardio for an hour. The typical is only for 15-30 minutes. You don't need to have a bucket of perspiration to stop and assume you lose lots of fats. Yes, you will lose lots of fats, but it will affect your energy.