http://www.ideafit.com/fitness-library/short-burst-trainingIn old-school thinking, accessing fat both stored and free-floating in the bloodstream required endurance-type “aerobic” training. Aerobic means “with oxygen,” and the physiological pathway initiated in the presence of oxygen utilizes fat for fuel, making it the superior choice. But recent research opens the door for a new theory—that high-intensity training is even more effective. One such study compared the effect of a 20-week endurance-training program with that of a 15-week high-intensity program in terms of body fat loss and muscle metabolism.
Researchers found a larger reduction in subcutaneous fat in the high-intensity group, despite noting that the total energy cost between the two groups indicated higher caloric expenditure for the endurance group. Furthermore, “when corrected for the energy cost . . . the reduction induced by the high-intensity program was nine-fold greater than the endurance program” (Smith 2002).
Another study, published in the Journal of Applied Physiology, measured skeletal muscle fuel content, fatty-acid transport proteins, and hormonal and other responses in women after a 2-week SBT program. Results indicated that “seven sessions of SBT over 2 weeks induced marked increases in whole body and skeletal muscle capacity for fatty acid oxidation during exercise in moderately active women” (Talanian 2006).
Traditional aerobic training is also praised for improving the body’s efficiency at burning stored fat once activity ceases, a phenomenon termed excess post-exercise oxygen consumption, or EPOC. But more and more studies are showing that the EPOC created by high-intensity training induces a response that renders the body even more efficient at burning fuel. For example, a 1996 study in Medicine & Science in Sports & Exercise comparing endurance- and interval-trained subjects showed that “the interval group burned more fat during exercise . . . [and] exhibited increased fat burning effects that persisted for 24 hours after the exercise had stopped” (Treuth, Hunter & Williams 1996).
In a 2001 study, researchers compared two groups, one exercising aerobically and the other using interval training. Both groups burned exactly 300 calories, but despite exercising longer, “the aerobic group lost less body fat” (King et al. 2001).