Try Interval Training. It Pays.

from exercise.about.com

For the longest time, most of us thought that the only way to burn fat and calories was to trudge through long, steady workouts, watching the minutes tick past at a glacial pace. While there's no doubt that those slow, steady workouts have a place in any routine, particularly for building endurance, there's another type of training that offers different types of benefits: Interval training. This type of training, which involves alternating high intensity exercise with rest periods, makes workouts more fun and it can also:

Enhance athletic performance
Boost your cardio fitness
Accelerate weight loss
Improve your body's ability to burn fat
Make your workouts more time efficient More