Re: How much exercise is enough?
Sabriya, 45 minz on the treadmil is great.
I do suggest however that you include stretching before and after using it and warming up and cooling down. Doing so is an integral part of your workout and must be included. I didnt see any mention of this in your post.
As far as spending 1 hr on the machines.... It's a personal choice how many hrs you want to spend at the gym. Just be sure you are not working out the same muscles everyday. Your muscles need a break to recover and overworking them can cause more harm then good. Once again, be sure to stretch out each muscle before and after working them out. You are more suseptible to injury if you dont.
The amount of time you want to spend on each machine depends upon what you are trying to achieve. I personally use heavy weights, and do less reps and about 3 sets. But once again...that's just me. You may find your own way of doing things.
If you think that 2 hrs isnt enough then perhaps you are not making it challenging enough for you because 2 hrs is more then enough time to get a good workout. You should be able to feel your muscles burn..if not then I would increase the weights you are using.
workout morning, noon, or night....just do it whenever it fits into your schedule and be consistent about it.
Lastly, the amount of calories you should burn depends on what you are trying to achieve.