Cardio Fitness

I'm working out 3-5 times a week regularly, but now I've decided its time to speed things up a little. I will therefore start doing the Guerrilla Cardio, which is a 12 minute interval program, 4 times a week of to my ordinary workout. You can do this workout running, cycling, lifting weights... or whatever you think is a fun exercise! My choice is an indoor bike - even if its only for 4 minutes its a hard workout that pumps up the metabolism and burn fat. I commit to see some results in September... Wish me luck!
If you would like to try it for yourself this is how you do it:
Minutes 1-4:
Warm-up 50% perceived exertion
Minutes 5-8:
Sprint (100%) for 20 seconds
"Rest" (50%) for 10 seconds... repeat...
Minutes 9-12:
Cool-down at 50% perceived exertion

Good Luck!