Many people dread having to do long-duration, steady-state cardio. For one, it can be boring, and two, not many people have the time to spend hours doing cardio each week. Sprinting is an effective alternative that improves aerobic endurance and burns a lot of fat. The best sprints for cardio exercise are all-out, maximum-intensity, long-duration sprints, because they totally exhaust your muscles.
Sprinting is not just for sprinters or individuals looking to burn calories in a short amount of time. Sprinting also benefits distance athletes by improving aerobic endurance. Aerobic interval training involving repeated bouts of high-intensity sprints separated by brief rest periods generates aerobic benefits because the rest periods are so short that full recovery cannot occur, thus stressing the aerobic system, according to Jack H. Wilmore and David L. Costill, authors of the "Physiology of Sport and Exercise."
The body typically burns a larger percentage of fat for energy during exercise at lower intensities and more carbohydrates for energy at higher intensities. Theoretically, to burn fat you should perform cardio at a lower intensity, but lower-intensity exercise burns less calories than higher-intensity exercise. So, by performing harder, higher-intensity activity, like sprinting, you will burn an overall greater amount of calories, thus increasing the amount of fat burned.
High-intensity interval training, or HIIT, involves short bursts of sprinting followed by brief low-intensity recovery periods. In 30-second sprints, after warming up for at least five minutes, sprint all out for 30 seconds, then walk for 30 to 90 seconds for recovery. Beginners should walk the entire 90 seconds and gradually reduce the recovery period over time. The intervals then should be repeat six to 12 times. Finish your workout with a five-minute cool-down.
The longer intervals completely exhaust your muscles of their stored energy. This energy will take 24 to 48 hours to replenish, according to the Interval Training website. Long interval sprints last about 60 seconds with recovery intervals between 120 to 60 seconds. Perform six to 12 long-duration intervals, gradually increasing the number of intervals and decreasing the recovery interval time as you progress. Combine long and short intervals into your weekly training schedule for maximum fat loss and aerobic endurance benefits.