Is this such a good thing? No one should be looking for weight loss but fat loss unless you're some crazy sportsman needing to drop lean weight for a weight class or something but 99 % of the general public want fat loss. Now if you train at a lower intensity using your aerobic system in your optimum fat burning zone you will burn fat but no calories after that. Thats great as those calories if your diet and training is correct can go towards building muscle. It is easily possible to build muscle and lose fat at the same time. I agree high intensity training is better for weight loss but not fat loss.
Even though you burn more fat going slowly, you still burn a percentage of fat at much faster speeds or intensity. It all boils down to how much energy you expend in totality. For example, if you compare exercising at a slow rate that burns 60 percent fat and 40 percent glucose and a higher intensity or duration that burns only 30 percent fat and 70 percent glucose, you may still burn more fat at the higher intensity.
A typical example. Exercise (1) is the slower 60/40 mix and exercise (2) is the faster, 30/70 mix of fat and glucose fuel.
Walking on a treadmill for 30 minutes -- 180 calories used -- 108 calories of fat burned
Running on a treadmill for 30 minutes -- 400 calories used -- 120 calories of fat burned
You can see from this example that the bottom line really is how much energy you expend -- and that is the ultimate fat burning measure. The theoretical fat burning zone is mostly a convenient myth.
This is an example of doing exercise at a Higher Intensity only and not High Intensity Interval Training. Maintaining a higher metabolic rate and burning more calories at rest over a 24 hour period produces Fat loss.
This is how HITT is preformed:
The High Intensity Interval Training (HIIT), also known as the Tabata Protocol, was developed by the head coach of the Japanese speed skating team. It was named after Dr. Izumi Tabata because Tabata and his team (at the National Institute of Fitness and Sports in Kanoya, Japan) studied the speed skating coach's workout to determine the optimum protocol.
A 4 minute cardiovascular training routine has been proven to improve fitness. The whole session last 14 minutes and comprises of a 5 minute warm up, 4 minutes of intense exercise and a 5 minute cool down. The 4 minutes of intense exercise comprises of 8 repeats of 20 seconds of maximum effort work of your selected exercise followed by a recovery of 10 seconds.
This type of exercise is short in total time, so you don't get catabolic and start burning muscle as an energy source.
The Benefits
In Tabata's study, the researchers found that athletes who used the routine five days a week for six weeks improved their maximum aerobic capacity by 14% and improved their anaerobic capacity by 28%. A study of traditional aerobic training of running at 70% of aerobic capacity for 60 minutes for six weeks showed an improvement in aerobic capacity of 9.5% and no effect on anaerobic capacity.
Dr. Tabata's Team found that as well as improving your aerobic and anaerobic capacity it is very effective in lowering the ratio of lean body mass to fat without compromising your muscle size.
How to approach HIIT
The work to rest ratio of the original Tabata Protocol is 2:1, however, this was designed with olympic athletes in mind. A gym user can still attain many of the benefits of the interval training with a change to the ratio. A beginner could start with a ratio of 1:3 and someone who goes to the gym on a regular basis may be about to handle a 2:3 or even a 2:2. Here is an example of a 2:3 ratio Tabata Protocol on a static bike.
Warm up - cycle at 50% max effort for 5 minutes
Sprint for 20 seconds
Easy spin for 30 seconds
Sprint for 20 seconds
Easy spin for 30 seconds
Sprint for 20 seconds
Easy spin for 30 seconds
Cool Down - cycle at 50% max effort for 5 minutes
A professional athlete or an athlete with a number of years experience of training (3-5 times a week) should aim to actually do the original form of the Tabata Protocol. This interval training is incredibly difficult to complete 8 repetitions so for the first time an athlete should do it for 4 repetitions and see how they feel. An athlete can repeat cycles of the intervals a certain number of times. Here is an example of a football player doing the Tabata Protocol at a ratio of 2:1 for 6 repetition with 3 cycles and 1 minute rest between cycles:
Warm up - Jog at 50% max for 5 minutes
6 x (Sprint for 20 seconds + 10 seconds rest)
1 minute rest
6 x (Sprint for 20 seconds + 10 seconds rest)
1 minute rest
6 x (Sprint for 20 seconds + 10 seconds rest)
1 minute rest
Cool down - Jog at 50% max for 5 minutes.
The Tabata Protocol can be adjusted to anyone's level and activity (cycling on a static bike, running on a treadmill or track, swimming etc.).
I could hardly believe the benefits of HIIT whan I first discovered it, but I do now.
This is a decent read on the subject.
http://www.snay.org/menshealth/forums/hiit-vs-lsd.pdf