High intensity interval training (HIIT) is an incredible way to burn fat without losing muscle mass, as is common in almost all aerobic activities. HIIT, in fact, can help you build muscle up and improve your overall level of conditioning in a relatively short period of time, as compared to traditional cardio workouts.
HIIT is highly misunderstood, however. For example, there are many who hold firm to the belief that they must maintain a consistent level of output for an extended workout duration to burn a maximum amount of fat. And this is true, but inaccurate.
The factual part of this belief is that the longer you perform an aerobic activity, the more calories you will burn. Actually, your body will gain roughly 50 percent of its energy for this workout from your fat stores. Not considered, however, is that these long sessions also force the body into a catabolic state, where it will begin to eat its own muscle tissue for energy. So the end result is weight loss consistent of both fat and muscle. Good, but not ideal.
HIIT sessions, on the other hand, only consume 40 percent of their energy from fat stores, while participating in the workout. What this ignores is the fact that interval training raises your resting metabolic rate for up to 24 hours after finishing a HIIT session. Whereas aerobic activities burn fat for the duration of the workout, HIIT sessions burn fat for an entire day!
The bottom line is that HIIT sessions have been shown to be 200 percent to 900 percent more effective at burning fat than traditional cardio, depending on what numbers you believe. But again, HIIT sessions also spare your muscle mass. They even help build muscle up. So not only are you burning more fat, but you're also building more muscle, which helps your body burn even more fat in the future.
Another nice benefit of HIIT sessions is that they do not need to be performed for as long or as often for the fitness benefits. For example, you might work out 4 to 5 days a week, 40 to 60 minutes per session with typical cardio. With HIIT, you will workout 2 to 3 times per week, for 15-minute sessions. And you will get more benefit from your workouts to boot.
Just remember, HIIT is not for everyone. If you have any health problems, are not already in decent shape, have joint problems, or are over 60 years of age, consult your doctor to determine if HIIT is a good addition to your workout.