The best cardio workout you can do is also the shortest.
It is called the Tabata protocol after Dr.
Izumi Tabata who discovered in the 1990s that, by doing 8 short but highly intense periods of exercise for 20 seconds each period with only 10 seconds of rest in between you can increase your anaerobic capacity 28%.
This is only 4 minutes of work but it is highly intense.
This may not be for everyone though, but you can apply the principle to anything.
High intensity interval training is training intensely for brief periods of time followed by short periods of rest before you move on to the next exercise.
I have been doing this type of training for a few weeks now with a kettlebell and I find it difficult to last any longer than about 15 to 20 minutes in my workouts.
If you are unfamiliar with a kettlebell it is a Russian device that looks like a cannonball with a handle.
Because of its design it is ideal for swinging.
So this adds a weight lifting element to your cardio routine.
Because of this you will be winded pretty quickly using a KB.
The KB is so effective at building anaerobic capacity that I have heard of people running marathons after doing nothing but working with a KB.
KBs are also extremely effective at burning fat.
Research has shown that you can burn up to 20 calories a minute using a KB which is the equivalent of cross country skiing uphill.
Now, if that is not a great cardio workout, I don't know what is.