> it's going to take you a long time to get fit, Not really - you'd be suprised how much energy is expended on this change of state (and the stress that accomp

> it's going to take you a long time to get fit, Not really - you'd be suprised how much energy is expended on this change of state (and the stress that accompanies it) as opposed to the paced effort of learned distance running. That's what HIIT is based on, and I'd argue that for an average unfit person it's much easier to quickly expend lots of energy than for a trained athlete.