Most people do their cardio wrong.By wrong, we mean they decide to stick with long, boring cardio like walking.Well, although that's better than nothing, in order for cardio to be effective, you need to make sure it's intense enough to do one thing.Raise your resting heart rate and metabolism. And to do this, cardio needs to be short and intense.See, when you do cardio at an intense level, you not only burn more calories in a shorter amount of time, but you also raise your metabolism and your resting heart rate.This is important because when you do this, your resting heart rate remains elevated all day long. In other words, all day long, you'll be burning more calories than if your resting heart rate was lower.A lot of people don't realize that one of the main reasons cardio helps to burn body fat is because it increases your metabolism, or resting heart rate.Sure, while you're running, jogging, doing the Elliptical, or Stairmaster... you're burning some calories than. But those are minimal... probably 200 to 300 calories during a 30 minute session.But here's where the magic lies. When you do your cardio intense, and do short bursts of intense, difficult cardio for 20 to 30 minutes... you're going to raise your resting heart rate so that it remains elevated all day long.That means, while you're resting, watching TV, playing golf, walking the beach... no matter what you do, you're metabolism is going to be higher. And because of that, you'll be burning more calories during the day than you would if you DIDN'T do an intense form of cardio during your workouts.So, the good news is, you don't have to spend a ton of time each day doing your cardio.But what you DO need to do, is make sure you're doing it at the most intense level you can.This is when you get the full benefits. You get the benefit of healthier lungs, better circulation... but from a fat loss stand point, you get a higher resting heart rate and metabolism. And you get to enjoy this higher metabolism all day long, which means you'll be burning calories throughout the day, no matter what you're doing.An intense, 20 minute all out cardio session on a recumbent bike will do more for your fat loss than an hour long walk. It's not always the amount of time that matters, it's the quality.Just like weight training, it matters more HOW you do your cardio than the time you spend. Remember, our goal is for cardio to be short and intense.For example, just lifting 10 pound dumbbells for the next year won't exactly give you those sleeve busting biceps you want. You need to keep lifting heavier weight, so your muscles grow and respond to the overload. That's how muscle gains happen. You continuously overload and stress the muscles with heavier weight, so that it responds by getting bigger, to handle the weight.So, the key is to always be improving the amount of weight you lift. Well, the same is true of cardio. You always want to try and keep increasing the intensity so you increase the benefits you get from it.In order to keep increasing your resting heart rate and metabolism, keep trying to up the intensity of your cardio sessions. The best way to do that is to keep them short and intense.That's why brief cardio sessions are better than longer ones. When you only have to go for 20 minutes, you can give it your all.. the highest intensity possible.That' much harder to do when you're going for an hour. Scientific studies have shown that 3 to 4 sessions of high intense cardio each week, with each session lasting 20 to 30 minutes, is sufficient to keep your metabolism elevated and the fat burning process going.So, always remember that your cardio sessions aren't that effective when it comes to burning calories WHEN you're doing it. No, the real pay off happens AFTER you do your intense cardio. That's because the intense cardio increases your resting heart rate, or metabolism, so you burn more calories all day long, even while you're resting.So bottom line, keep cardio sessions short but intense. Stick with 3 to 4 sessions a week, at no more than 20 to 30 minutes each.This higher intensity session will have a bigger effect on raising your metabolism and resting heart rate than lower, slower exercise like walking.If you remember that short bursts of high intensity cardio conditions your body to burn more calories and body fat AFTER you do it, while you're resting throughout the day... you'll be more willing to stick those hard, intense sessions out, knowing that doing them will help you burn fat all day long, even while you're just hanging around on the couch later on in the day.