A lot of people wonder, "What's the best kind of cardio"? "What will burn more calories, the treadmill or the elliptical trainer"? "It must be the stair master. That thing makes you sweat like no other".
It's much more simple than that. The best kind of cardio is the kind you like to do.
There's nothing that kills motivation more than dreading the exercise you're about to do. Especially when it comes to cardio. I mean, really! Who wants to go crazy for 30 minutes (at least)! You like running every day? Great! That's the best kind of cardio for you. The key to making it the most efficient type of cardio is to make sure you keep track of your Target Heart Rate.
With Target Heart Rate training, it will maximize your workout. You won't wast your time working out too hard or not hard enough. You can workout at different intensities to achieve specific goals. By having a specific, scientific number to work from, you're pretty much guaranteed success (provided the rest of your program is on spot).