I think maybe we're getting off topic, but I've got asthma and I don't think you'd burn more calories. The working out itself doesn't bring on my attacks, but if I'm having difficulty breathing when I start working out, I just can't finish. So based simply on the fact that you can't last, I would say no. But I see what you're saying, if you're struggling to breathe, does it burn more calories in the same time frame. You're more fighting to breathe than anything else. Also, to follow up on that same topic, I wonder if lack of oxygen intake (due say to asthma) could actually inhibit burning calories?