OK. This is probably pretty trivial. I searched and could not find an article about it. The machine I use at the gym as a Interval setting. It has 1 minute of low resistance then 30 seconds of higher resistance. If I sprint on the 30 second intervals I burn about 400 calories in 20 minutes. However, I have also found that if I up my pace and keep it the same for the whole program I can still burn 400 calories in 20 minutes.

My confusion lies in the fact that keeping the same pace is not HIIT, but is it HIIT if there are higher resistance intervals.

Interval training isn't the same as HIIT. Interval training is generally used to help increase a runner's pace, rather than simply to burn loads of calories.

It sounds like the intensity on this programme simply isn't high enough for you to be doing HIIT.

Here is a decent article on HIIT: click (http://www.youronlinefitness.com/Fitness_Articles/articles/January_2003_articles/hiit_and_other_interval_training.htm)