I've done the couch to 5k program twice, and I loved it. The first time I literally went from the couch to running a 5k. I didn't exercise at all and the 30 seconds of running during day 1 was seriously leaving me winded! But, I completed my first 5k just 12 weeks after I started. It was awesome! The second time I did the program was to get myself to run faster. I wasn't sure how to train my body to do so otherwise. So instead of running at a speed of 5, I ran at a 6, etc. It helped and was pretty awesome. Good luck!!