question about cardio ....

So I cant seem to find it anywear but how much cardio are you supposed to do (at a time and per week)  Ive heard many different things and was just wondering???  Thanks

Depends on why I guess. I think they claim to be healthy you should shoot for 20+ minutes 3x a week.

Outside of that it depends on your goals.

I've heard that doing about 180-200 minutes of cardio a week decreases a woman's risk for breast and cervical cancer significantly, along with heart disease. i'm not sure about men...but i shoot for an hour 4-5x a week. if you want to lose weight, i guess you would do more than if you're trying to just build muscle by doing weights.

Here's an excerpt from this article, quoting the surgeon general's recommendations:

The U.S. Surgeon General,(1) along with the Centers for Disease Control and Prevention and the American College of Sports Medicine,(5) recommend getting a minimum of 30 minutes of moderate-intensity physical activity on most days of the week. You can do all 30 minutes at once or break it up into 10- or 15-minute periods.

Moderate intensity exercise or physical activity is activity that causes a slight but noticeable increase in breathing and heart rate. One way to gauge moderate activity is with the "talk test" - exercising hard enough to break a sweat but not so hard you can't comfortably carry on a conversation.

I read at the gym once that you should do at least 30 minutes of cardio at a time to get the full effect - so my 20 minutes I was regularily doing at a time had to be boosted up... but don't quote me on that... it's just something I read on the eliptical at the gym...