It depends on your goals and what you are working out for.
If you are training to be competitive at a triathlon than you will need to work out several hours every day. If you are trying to do some strength training to stay toned and cardio for endurance and health than 20 minutes is a pretty good workout; perhaps 40 if you do strength and cardio on the same day.
You shouldn't have to work out more than half an hour to an hour if you are doing it properly if you do it any longer your heart rate starts to slow down. Most people at my gym go to socialize and spend hours there.
Angelee is correct, 30 minutes a day should maintain your current body shape and keep you healthy and an hour should promote weight loss. Remember to take off at least one day a week so you can rest
stick to one hour......anything more and your not working out hard enough and anything less and your not working out hard enough...
No...you can work out for however long you want. However, 30 minutes to an hour a day is ideal. You don't want to over-due it...
no but sometimes it could be bad 4 you. have u ever heard of people getting really sick from working out?