Hi Emily. I asked the same question on here the other day! It is my understanding that you do a 5-minute warm up, then 20 minutes of intervals, for a total of 25 minutes.
Don't forget the 5 minute cool-down walk, taking the total to 30 minutes.
My blog: Folly or Feasible?
Hi I finished Day 2 Week 2 yesterday Saturday and planning to do Week 2 Day 3 tomorrow morning. I have lost 30 pounds but need to lose abot 100 more. I have been doing pretty good so far; I am wondering how Week 3 will be.
I downloaded an app for my iphone for C25K and it has you warm up for 5 min; do your running/walking the next 21 min and cool down for 5 minutes in the first week for a total of 31 min. The second week, warm up 5, running/walking 19 min and cool down for 5 minutes for a total of 29 min. I love the app which dings and also tells me out loud when to walk and when to run.
You might also check out the Running Mate 5K 101 program. It;s an 8 week gradual program with a set of coached podcasts that go with it which are also set to good running music. Here's the link if interested: www.5K101.com