Not only do sprints help you lose more fat, they help you lose it faster and with less training time. Repeatedly, studies show that more fat loss is achieved in high-intensity programs that use 20 to 25 minutes of training time, than those that use 45 or 50 minutes of aerobic training time.
Scientists write that anaerobic intervals are overwhelmingly preferable to aerobics for producing fat loss, and that the estimated optimal dose of aerobic exercise necessary to lose belly fat appears to be 3,780 calories expended per week. This is an enormous volume of exercise that would require one hour of moderate intensity aerobic cycling seven days a week to burn 550 calories a day so that you could lose just one pound per week.
In less than half the time you can get better results with anaerobic training. A 1994 study compared participants that did either 20 weeks of aerobic training or 15 weeks of intervals. The interval group did 15 sprints for 30 seconds each, and lost nine times more body fat, and 12 percent more visceral belly fat than the aerobic group.
What really makes for a convincing case is that the energy cost of the aerobic program over the whole study period was 28,661 calories, but for the interval group it was less than half, at 13,614 calories. In less time, the interval group lost nine times more weight. This can be explained in more scientific terms.
Aside from greater fat oxidation and higher EPOC, hormone response plays a major role as well. Sprint intervals and anaerobic exercise in general improve your entire endocrine system. These training modes enhance the cells’ sensitivity to insulin, making anaerobic training a successful treatment for diabetes.
Even more important, anaerobic exercise also elevates growth hormone, which is a powerful fat burning hormone that helps restore tissue and build muscle tissue. Growth hormone is released by the body in greater quantities in response to physical stress above the lactate threshold, which is the reason heavy, anaerobic sprints are so effective.
Another hormone called adiponectin that is released from fat tissue during exercise, also helps burn fat. Emerging scientific evidence shows that any time you perform forceful muscle contractions, adiponectin is released, and your body produces a substance called PGC1 as a result. PGC1 enhances muscle and metabolic functions, which in turn will use fat for your energy needs more efficiently. Naturally, anaerobic training is most effective for increasing adiponectin and PGC1 to lose body fat since sprints, and even more so, weight lifting require extremely forceful muscle contractions.
In order for all of this to work you need to strength train with a high volume with a focus on the large muscle groups, and employ only short rest periods. This metabolically intense type of training is fantastic for increasing growth hormone release, which is extremely effective at aiding in fat loss.
Use multi-joint lifts such as squats, deadlifts, lunges, split squats, step-ups, chin-ups, and chest presses in every training session. Only use isolation exercises only if you have extra time. Aim for 24 to 32 total sets per training session, and do those using 70 to 85 percent of your one rep maximum. Short rest periods of 30 to 60 seconds are all that should be used, and use a final exercise that requires near maximal effort for maximum growth hormone response, such as a 25 rep set of squats or deadlifts. Make sure to use slow eccentric tempos, and short or explosive concentric tempos.
Another reason that anaerobic training is the way to geo in order to get a lean muscular body is because of the stress hormone cortisol. Cortisol is elevated when you are under both physical and psychological stress. Research shows cortisol is chronically higher in endurance athletes, and one study found that aerobic athletes had significantly higher evidence of cumulative cortisol secretion in their hair than did the control group. This means that cortisol is generally elevated more following aerobic training than anaerobic training. Part of this has to do with the fact that strength training and intervals elevate cortisol, but they also elevate anabolic hormones such as growth hormone and testosterone. These counter the negative effects of cortisol.
When growth hormone and testosterone are not elevated, cortisol overwhelms tissue, having a catabolic effect that leads to gradual muscle loss and fat gain. By doing aerobic training without strength training, you will lose muscle, lower your metabolic, rate, and gain fat. What may even be worse is that high cortisol causes chronic inflammation, which leads to more fat gain over time.
Another advantage to doing intervals and strength training, is that they provide much more variety than aerobic training. In addition, most people enjoy feeling powerful, and fast. Having a training partner to push you will go a long way to helping you reach your fat loss goal.