Check your grammar now! : intense or paroxysmal excitement; especially : the rapid pleasurable release of neuromuscular tensions at the height of sexual arousal that is usually accompanied by the ejaculation of semen in the male and by vaginal contractions in the female.
So, even though you may have only burned 250 calories during your HIIT workout, the total calories burned after will be far greater. Those calories, plus the 250 burned during the HIIT workout surpasses the 400 burned during the slow, steady-state workout by a LONG, LONG way.
The good news for you, however, is that if you decide to make HIIT your primary form of cardio, there are several tweaks you can throw in to enhance the process and get the fat off much faster. The first of these tweaks applies to how you space out your workouts.