I have a couple of questions for you knowledgeable ladies:

1. How long does one need to work on building a base? I'm not coming from the couch, I have been hiking, snowshoeing, weight lifting and going to aerobics classes for years. I started cycling last year. Running has been off and on, never more than a 5k, I'm working on slowly increasing my distance now. But I've never done anything close to a structured training program. Since I got my hrm, I've discovered I actually enjoy running if I keep to an easy zone 1 - 2. However I'm itching to start some interval work. I've been doing the slow runs for about 6 weeks now, can I start doing intervals yet?

2. If the guideline is to do intervals once a week, does that mean I do one run interval workout AND one bike interval workout? Or do I have to pick one, either run OR bike, for the week?

Thanks!