It’s Efficient
Super-efficient HIIT is the ideal workout for a busy schedule—whether you want to squeeze in a workout during your lunch break or to get in shape for a fast-approaching event. Research shows you can achieve more progress in a mere 15 minutes of interval training (done three times a week) than the girl jogging on the treadmill for an hour. (Watch and try this video of a 10-minute fat-blasting cardio routine that burns more calories than a half hour on the treadmill!) And according to a 2011 study presented at the American College of Sports Medicine Annual Meeting, just 2 weeks of high-intensity intervals improves your aerobic capacity as much as 6 to 8 weeks of endurance training.
You’ll Burn More Fat
Not only do you burn more calories during a HIIT workout, but the effect of all that intense exertion kicks your body’s repair cycle into hyperdrive. That means you burn more fat and calories in the 24 hours after a HIIT workout than you do after, say, a steady-pace run.
You’ll Build a Healthier Heart
Most people aren’t used to pushing into the anaerobic zone (that lovely place where you can’t breathe and you feel like your heart is trying to jump out of your chest). But in this case, extreme training produces extreme results. One 2006 study found that after 8 weeks of doing HIIT workouts, subjects could bicycle twice as long as they could before the study, while maintaining the same pace.