Simply put, high intensity interval training is the mother of all cardio workouts. If you want to get the absolute most out of your cardio workouts in the least amount of time possible, then integrating high intensity interval training is something you should definitely consider. Be warned that this form of training is not easy and as the name states … very INTENSE! You should only attempt serious interval training if you are already in reliably good cardiovascular shape and have a high level of anaerobic fitness.
It is a form of training in which you work at close to 100% as you can for a short time followed by a rest period and you rotate on and off. Let's look at an example. Let's suppose you are on an elliptical machine. After you are properly warmed up and ready to start, you would go as hard as you could for 30 seconds or a minute. When that 30 seconds or a minute is up, follow it up with 30 seconds or a minute in which you slow things down, catch your breath, recover, rest, and get ready for the next "on" interval. When the 30 seconds or minute is up, rev the intensity all the way back up and work as hard as you can for the next 30 seconds or minute and then bring it back down. You would simply alternate like this for 20 or 30 minutes.
Now if you're just starting out, I suggest 30 seconds on, 1 minute recovery and from there trying to work your way up. The more advanced you get and the more in shape you can get, it is possible to do intervals where the "on" periods are longer than the "rest" periods. For example working hard for 1:30 and resting for a minute. However, do not attempt this until you are in excellent cardiovascular shape.
The benefits of high intensity interval training are numerous. One thing this form of exercise allows you to do is burn a ton of calories during the workout. By working at such a high intensity, the amount of energy you expend and the number of calories you burn is high. I have had 20 minute interval training sessions in which I've burned more calories than 30 minutes at a steady moderate intensity. Interval training is a great way to burn lots of calories and really get your heart rate jacked up.
The real benefit of interval training is what happens after the workout. Because you have worked so hard and gotten your heart rate so high, when you are done working out your resting metabolic rate is elevated that means you burn will burn even more calories. I like to call this the "after burn" effect of interval training.
The fact is high intensity interval training is the mother of all cardio workouts. You will burn tons of calories and give yourself an unbelievably intense workout as well as experience the "after burn" effect. Anyone looking to take their cardio training to the next level and get a super intense work out should consider high intensity interval training. You will not be disappointed I can promise you that.