Burn more AFTER your cardio workout.

You can see it on the weight room floor, on tracks, and on the cardio equipment.  Interval training has slowly been replacing  long slow distance (LSD) training as the preferred route to burning calories.  And because burning calories (i.e. weight loss) is the most popular goal among those starting a fitness program, understanding why this switch has been taking place is important.
One of the primary reasons for the switch to interval type training is its effectiveness, and one of the main drivers is the concept of excess postexercise oxygen consumption (EPOC).
EPOC is the amount of oxygen an exerciser has to take in to restore the body to preexercise condition (recovery).
When interval training, often the “bouts” of action are between 15-60 seconds, thus requiring ANAEROBIC mechanisms to supply energy for the work.  Following an interval session (containing several bouts of anaerobic “sets”) the caloric cost of returning the body to it’s preexercise state is very high, and the “burning” has been observed in some studies to last up to 24 hours after exercise. 
So, although an exerciser may burn more calories DURING a steady state aerobic exercise session, the effects of EPOC after an interval training session have been shown to out-do (as far as caloric expenditure is concerned) traditional slow cardio.  Interval training is a time-efficient, effective way of burning calories.
Matt Pirtle, M.A., CSCS
Emerge Fitness Training
St. Charles, Missouri