Re: does time play a role?
You'll get a lot of different answers, but I personally think it does matter. But it depends what type of exercise you're doing. Is it weight training or cardio? Is that cardio steady-state cardio that you can do for at least 45 minutes or is it interval training?
Exercising more than once per day might not be necessary. It depends on how your body reacts to exercise. Some people are lucky and can just do a coupd evenings of cardio and a couple evenings of weight training and never need to exercise more than once per day. Others, like myself, don't see significant results unless I exercise twice. I run in the morning and then do weight training 3 evenings. But there's no one routine for everyone. Unfortunately, you just have to do a lot of trial-and-error. And like you said, there's always the issue of overtraining. If you're not seeing the results you like, first take a look at your diet. Find ways to clean it up before you start tampering with your exercise routine.