The benefits of high-intensity interval training (HIIT) have been clear for a long time, but it’s only within the last few years that it’s really started to gain popularity. Studies, including one published in Metabolism as early as 1994, have found it to be better than steady-state cardio when it comes to building or maintaining muscle mass while burning fat.

What Is HIIT?

HIIT workouts alternate short bursts of intense effort and slower rest periods that are one to two times as long; for example, sprinting for 30 seconds, then jogging for one minute. To get the maximum benefit, the “work” interval should get you up to 80 to 90 percent of your maximum heart rate, and the “rest” interval should let it drop back down to 40 or 50 percent.

Why You Should Try It

HIIT workouts…

  • Are extremely efficient: They burn up to 12-15 calories per minute.
  • Create the “after burn” effect: When you do HIIT, your body continues to burn calories for up to two hours after your workout, resulting in up to 15 percent more calories burned.
  • Increase aerobic capacity: This means your body can work harder, faster, and longer.
  • Raise lactate threshold: Which means you can do tougher workouts.
  • Increase insulin sensitivity: While we usually think of insulin sensitivity in conjunction with diabetes, in the context of exercise it means your body can more easily burn glucose for fuel during a workout.

Make Your Workout a High-Intensity Workout

Nearly any cardio activity can become an interval workout. The length of the intervals will vary depending on your current fitness level and the exercise you’re doing, but a good beginner’s rule is to start with 10 to 30 seconds of high intensity work followed by 30 seconds to one minute of rest. If you’re just starting a workout plan, you may need to shorten the work interval or lengthen the rest period; if you’re already extremely fit, a 1:1 ratio may work for you.

Keeping track of seconds while you’re working all-out can be tough, but there are a variety of apps available that can help you. A HIIT interval training timer is basic but flexible, while Seconds Pro for iOS has all the bells and whistles you could want.

HIIT requires a very long recovery period of about 48 hours, so take care not to overtax yourself. Beginners should only do HIIT workouts once per week, while fitness buffs probably shouldn’t do one more than two per week. Listen to your body and adjust accordingly.

Sources:

http://www.precisionnutrition.com/all-about-hiit

http://dailyburn.com/life/fitness/high-intensity-hiit-workout/

http://dailyburn.com/life/fitness/epoc-afterburn-effect/

http://www.metabolismjournal.com/article/0026-0495%2894%2990259-3/abstract?cc=y

http://www.ncbi.nlm.nih.gov/pubmed/7874151