You probably know that high-intensity intervals are more effective for body composition and fat loss than aerobic exercise, but the rest of the population appears to still be stuck slogging through miles with the hope of losing fat. It’s time to spread the word and let them in on the secret. This study compared the effect of a sprint interval program that included 30-second sprints with an endurance running program at 65 percent of maximal for 30 to 60 minutes over 6 weeks. Participants in the sprint interval group increased their volume from running 4 sprints with 4 minutes rest per session to doing 6 sprints per session by the end of the study. The endurance running group increased run time by 15 minutes every 2 weeks to reach 1 hour of training time per session. The sprint interval group lost an impressive 12.4 percent body fat and an average of 2 to 3 kg of fat mass by the end of the 6-week study. The endurance training group also lost about half a kilo of fat—not too impressive. The sprint interval group spent a total of. 75 of an hour actually sprinting compared to the endurance group that trained for 13.5 hours. That’s right—the sprint interval group spent 1/18th or 5.5 percent as much time training as the endurance training group and they lost way more fat. The total time required to complete the workouts including rest intervals was 6.75 in the sprint interval group compared to the 13.5 hours for the endurance group. The sprint intervals were likely so much more effective because they increased post exercise oxygen consumption, effectively elevating metabolic rate and energy use after the sprint workouts. Sprints also burn a lot of calories fast, and they enhance the function of enzymes and proteins that are involved in using fat for fuel.
Here are a few points to use when you plan your workouts:
• Researchers say running is better than cycling for fat loss, but they express caution about having novice trainees run at top speed, especially on a treadmill. You can avoid this problem by doing sprints at the track.
• Running up hills outside is another alternative.
• Modify interval length and intensity if you are deconditioned and just starting to workout. Longer intervals (1 to 2 minutes) in the range of 90 to 120 percent of VO2 max.
• If you want to run a 5K race, you don’t necessarily have to slog through miles to prepare. Just do sprint intervals, lose fat, save time, and you’ll increase speed as well.