Interval training has received lots of attention in the media, but does it really provide superior fitness benefits? The answer is yes and no. No in the sense that your metabolism does not stay elevated for hours after training. Nor does it burn significantly more kcal than cardio training. In our short research study, interval training and cardio training came out almost equal in how many kcal you burn per hour.
The real benefit of interval training is not the kcal you actually burn, but that you increase your ability to burn more kcal in steady state training. In technical terms, you elevate your Anaerobic Threshold. So, when you hop on that elliptical you can burn 10 kcal a minute versus 7 kcal a minute. Over 50 minutes, that really adds up in terms of weight loss or fitness benefit.
So, use interval training once or twice per week, and spend the balance of time in cardio training and that will likely provide a better fitness benefit.