By Lisa Steuer
High-intensity interval training was listed as the top anticipated fitness trend for 2014 in the November/December 2013 issue of the American College of Sports Medicine’s Health & Fitness Journal. It was the eighth consecutive year of the annual survey of health fitness professionals, and the survey helps the fitness industry make important decisions based on growth and development the following year.
Since high-intensity interval training continues to be a top fitness trend, let’s take a look at the science behind the workout and how to incorporate it into your own fitness routine.
High-intensity interval training is a method of exercising that constantly challenges your body, which is what makes it so effective. In addition, research has shown that HIIT limits muscle loss that can occur with traditional steady-state cardio workouts. So if you’re looking to preserve muscle while blasting fat, HIIT is definitely the way to go. It’s also been reported that the most effective cardio workouts combine high and low intensities— which is exactly what HIIT training consists of. As a result, HIIT tends to burn more calories because of the intense bursts.
What’s also interesting about HIIT training is that even though it is shorter in duration, it induces muscle metabolic and performance adaptations that are actually similar to longer duration, low-intensity exercise, but in less time. There’s also the “post-exercise” benefit of HIIT. For more than 24 hours after an HIIT workout, the body’s metabolism is increased, which means that even when you are done with your high-intensity workout, you continue to burn calories at a higher rate. In fact, a study by Canadian researchers found that, indeed, excess post-exercise oxygen consumption— which is a measure of additional calories burned— was higher following HIIT compared to endurance training.
An aerobics workout like jogging or cycling continuously for 20 minutes will burn about 150 calories at 70 percent of maximum effort. So what about interval training? According to a University of Buffalo study led by Luc Gosselin, 10 minutes of interval training at 90 percent effort burned 195 calories. For this study, the interval training included exercise-rest durations that varied between 30 and 90 seconds of exercise, and 30 and 60 seconds of rest at maximum effort.
Another study conducted by Perry and colleagues examined the skeletal muscle and whole-body metabolic adaptations that occurred following six weeks of HIIT. The researchers found that the HIIT training resulted in an increase in citrate synthase and cytochrome c oxidase, which means an increase in fat oxidation. The study also found an increase in the total GLUT 4 receptors, which are located on the muscle membrane and act as the doorways that allow insulin to transport glucose into the muscle. With the increase in total GLUT 4 receptors, benefits may include improved insulin sensitivity and decreased risk of type 2 diabetes, obesity and coronary artery disease.
Leading Australian fitness trainer and well-being expert Mark Moon is a firm believer in high-intensity interval training. Creator of the Get Fit Fast program, which includes workouts that combine strength and cardio for every fitness level, Mark has more than 15 years of experience as a master group fitness instructor.
To help us put the benefits of HIIT into practice, Mark shared a total-body, high-intensity interval training workout that can burn up to 1,000 calories.
1. You MUST always warm up for at least 5 minutes to ensure your body is ready for the intense work ahead.
2. You MUST always be working about and 8/10 perceived rate of exertion or 80 percent of your maximum heart rate in the working phases.
3. You MUST always focus on keeping perfect technique on every exercise to avoid any injuries.
4. You MUST get to the end of your working phase feeling like you couldn’t possibly keep going… if you don’t then you are not working to your maximum.
5. You MUST spend a good 10 minutes at the end of your workout to bring your body back to a resting state, to de-stress your body and bring yourself back to a resting/fat-burning state.
For more info on Mark Moon and the Get Fit Fast program, visit markmoonfitness.com.
Hazell TJ, Olver TD, Hamilton CD et al. Two Minutes of Sprint-Interval Exercise Elicits 24-hr Oxygen Consumption Similar to That of 30 min of Continuous Endurance Exercise. International Journal Sports Nutrition Exercise Metabolism, 22: 276-283, 2012
Gosselin LE, Kozlowski KF, DeVinney-Boymel L. et al. Metabolic response of different high-intensity aerobic interval exercise protocols. J Strength Cond Res 26(10): 2866-2871, 2012
Greenwood, Tracey. “The Ultimate Fat-Busting Cardio Workout,” FitnessRx for Women Feb. 2012: 72-74. Print.