I found an article that contains some pretty interesting claims on this very topic. In short, it argues that anger causes increased testoserone release and decreased cortisol release. Stay angry,...
The thing about HIIT is that it is focussed on intensity, not on speed. What you need to do is to figure out your max HR and then design a program around that. I like to work at a 2:1 work to rest...
Actually, you may be on to something here. The OP went out of his way to specify that the trainer is a woman. Trainers stay employed by convincing people that they will not achieve the same results...