So I was running with my best friend yesterday and she asked me if I thought she was working out too much. I didn't think so but I don't really know what too much is.

Both of us have sedentary jobs (like we seriously hardly move throughout the day) and so we joined a gym together and try to make up for that through exercising every day at the gym. Her workouts (a bit more extensive than mine) are basically 1hour on the elliptical with a 15 min warmup and 20 min cool down on the treadmill and weights after the whole thing.

The only reason I ask is because her bf was giving her flack for going to the gym so much and neither of us thought she was overdoing it. So I guess, I just don't really have any idea as to how much is too much?

It depends. Depends on things like calorie intake and nutrition, recovery ability, level of stress, your personality, intensity of exercise, etc.

She's not hurting? And the boyfriend's problem is not that she's spending so long at the gym but that she's going every day?

I'd look at boyfriend issues there before overtraining issues.

Too much would be if you or your buddy are getting injuries because of the workouts... An hour and a half / day is not too much at all if you're feeling good...

I also agree that it may be an insecure boyfriend issue...

It depends on how her body feels! It's about the body - if she's experienced, then her body can handle more. If not, then she might be doing too much. I actually just did some research on this for myself, as I think I might be overtraining and I found some interesting things about it. I'm gonna post about it on my blog on Tuesday.

Basically, if she feels tired and fatigued and sore all the time from the working out, she might be overtraining and should rest up and calm down with the workouts.