When I do HIIT, I actually never walk. I do a minute sprint and a minute jog alternatively. I actually prefer running. Usually do about 20 minutes of running or 40 minutes of jogging.
@ AF, if you actually plan on going to the gym, then doing some exercises or even light weights before the cardio can help burn more fat.
It's best to do Weights "AFTER" Cardio actually for a number of reasons...
The most significant being:
-Cardio gets the blood flowing to all muscle areas, it's a good warm-up to get your body the strength it needs for strong lifts.
-If you do Cardio after Strength-Training you will burn off some of the muscle you just gained. However if you do Cardio before-hand, you will be burning off mostly fat and then you can simply gain muscle right after the Cardio and not worry about losing it.
Since afterall Cardio burns fat to muscle on a 3:1 ratio. (75% fat-25% muscle)
Oh and Chocolate Milk is the #1 drink for after-workouts, if you didn't know.
There are a million reasons why.