couple of questions
 

I am riding my stationary bike for 45-50 minutes per day, or atleast that is my goal. I have to wait until my baby is napping and have to get off when he wakes up because he likes to play with the pedals. Is it worth it to say get on my bike for fifteen minutes 3 times per day equalling 45 min? There are some days my son doesn't nap at all, and even though I try to get on it , I can't listen to him scream for 45-50 minutes in his play pen (all at once).

Second question is how long should I be aiming for strenght training I have a weight machine that is primarily for arms (but a few for the legs). Is it better to aim for number of sets or minutes doing it.. I generally do 3 sets of 15 reps for each different exercise.

I'm no expert, but based on what I've read, 3 sessions equalling 45 minutes is fine! Just be sure you're putting in an effort when you do them. And you're smart not to use it when your baby is apt to get too near. A woman I used to work with had her dd lose part of finger from putting it into the wheel. :eek:

I don't know much about home weight machines, but based on common sense, I'd say aim for sets/reps. That way you'll do what you set out to, whereas if you say x minutes, you may not get as much benefit.

My fear is my son getting hurt on my equipment, my daughter stays away from it. I have it set up so when I am not using it he cant get near it. I try to wait until he is napping to workout that way I can pay attention to myself. If he is awake and my husband is home it isn't a big deal because husband takes care of him. I don't want to deny myself a workout because my baby won't take a nap. he will let me go for about 10-15 minutes I really want to get my 45-50 minutes per day in.