Thank you, Trigirl. Well, I can't string more than a single mile of "running" together, so not sure how respectable that is. Intervals will be the only way I can do running, and I wonder what my knees are going to do with this activity. Maintaining cardio fitness is my main goal. I know others run in addition to riding, so I knew I'd get some good answers here. I will absolutely listen to my body, start out walking a lot more than running, and... go from there! It has turned off quite a bit colder now, so I'm riding my trainer more. I'd like to do some running here at home just to see what I'm capable of, but want to spend every day possible in the saddle before I have to say bye-bye to the bike for a while.

My shoes are actually "trail" running shoes. Will those suffice for a few weeks? How do they differ from shoes for urban jogging? I may be able to do some jogging on the beach. Is that advisable for a newbie?