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5 Myths About HIIT (High-Intensity Interval Training) Debunked

author image Nick Tumminello
Nick Tumminello is the 2016 NSCA Personal Trainer of the Year and the owner of Performance University, which provides practical fitness education for fitness professionals worldwide. He is the author of Strength Training for Fat Loss and Building Muscle and Performance (both books published by Human Kinetics) and has produced 15+ DVDs. He writes a very popular blog at

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5 Myths About HIIT (High-Intensity Interval Training) Debunked
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You’ve probably heard again and again that high-intensity interval training (HIIT) gets people amazing results in fat loss and fitness training. HIIT pairs high-intensity exercise intervals with low to moderate-intensity exercise recovery phases. The American College of Sports Medicine surveyed more than 3,800 fitness professionals to identify the top 20 fitness trends worldwide for 2014, and High-Intensity Interval Training took the number one spot. As with many other popular fitness and nutrition trends (such as CrossFit or Paleo), there are plenty of myths out there about HIIT training. On the next slides we’ll debunk the myths to make sure that you don’t fall victim to any of these mistruths.

Myth #1: Everyone Can Do a HIIT Workout
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Myth #1: Everyone Can Do a HIIT Workout

Just like you would not run a marathon – or even a half marathon – without training, you also shouldn’t probably go all out on a HIIT workout overnight. According to Len Kravitz, Ph.D., professor at the University of New Mexico and Micah Zuhl, M.S., assistant professor at the Central Michigan University, you need to be careful when starting or restarting an exercise program. “Beginning with HIIT may increase the chance for injury and muscle soreness,” both Kravitz and Zuhl warn in a recent paper they published on endurance training. It’s better to start with low-intensity aerobic exercise until you can run for 30 consecutive minutes at a moderate intensity, they advise.

Myth #2: HIIT and SMIT Are the Same Thing
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Myth #2: HIIT and SMIT Are the Same Thing

Many people are actually doing supramaximal interval training (SMIT) and mistakenly calling it HIIT. HIIT involves performing high-intensity exercise intervals, interspersed with low to moderate-intensity exercise. SMIT, by contrast, involves performing all-out bursts of exercise, interspersed with full rest periods, or no activity. Confusion and mislabeling aside, SMIT could be a more effective training method. A 2013 study published in the European Journal of Sport Science looked at the endurance and sprint benefits of high-intensity and supramaximal interval training. The researchers found that SMIT led to greater improvements in performance than HIIT or continuous running. SMIT also provided the greatest benefits for physically active people, especially for women. You can’t always do SMIT training, as your body will become adapted to the type of stimulus, making your effort less effective. Plus, you’re also more likely to lose interest when you’re doing the same type of conditioning. That’s where HIIT comes in. Try incorporating both SMIT and HIIT training to make your workouts more comprehensive, effective and interesting.

Related: 4-Minute Tabata-Inspired Fat-Blasting Workout

Myth #3: HIIT Is the ONLY Workout You’ll Need to Lose Weight and Stay Fit
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Myth #3: HIIT Is the ONLY Workout You’ll Need to Lose Weight and Stay Fit

It’s no secret that a well-designed strength training program can significantly increase strength, power, athletic performance and physical appearance in both men and women. But, what many people don’t realize is the importance of muscle in the fat loss process. Put simply, muscle is metabolically active tissue, as it is the physical place in your body where fat is burned (i.e. used as energy). So, the more lean muscle tissue you have, the more calories/fat you’ll burn throughout the day, even while you sleep ─ because more muscle tissue requires more energy. Your body is like your car. If you put a bigger motor in your car, you’ll burn more fuel while driving. With this analogy in mind, having more muscle will help make your interval training efforts more effective by helping you burn more calories. This is why strength training and maintaining muscle with proper training and eating strategies is absolutely critical for fat loss. The winning workout plan combines interval training with a comprehensive strength training plan.

Related: 13 Benefits of Weightlifting That No One Tells You About

Myth #4: More HIIT Is Always Better
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Myth #4: More HIIT Is Always Better

Like the name suggests, high-intensity interval training is intense and pushes your body hard, so it’s important to allow for plenty of recovery time between workouts. You don’t want to do too much throughout the week. Using high-intensity interval training three times per week will give you the best results while limiting the risk of injury.

Related: Can You Do This Free 33-Minute HIIT Workout?

Myth #5: HIIT Is Better Than Steady State Cardio
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Myth #5: HIIT Is Better Than Steady State Cardio

With the popularity of high-intensity interval training, the standard 30-minutes of steady state aerobic training (like road work, treadmill, elliptical trainer or bike) has seemed to fall out of favor. Steady state cardio is often demonized for interfering with and even killing muscle gains from strength training. However, a 2012 study published in the International Journal of Sports Medicine found that adding low-impact aerobic exercise, such as cycling, will not jeopardize gains in strength or muscle size. In fact, this study found that in previously untrained men, aerobic exercise might increase their muscular gains. And, of course, aerobic training increases your aerobic fitness. Light to moderate aerobic exercise is a great method to use on recovery days ─ between the more intense anaerobic (conditioning) interval training days.

Related: 7 Reasons to Do Moderate Intensity Exercise More Often

What Do YOU Think?
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What Do YOU Think?

The benefits of HIIT are undeniable, but it’s important that you don’t become so obsessed with this method of training that you neglect other effective training methods that will add variety and diversity to your workout routine. Keep things in perspective. Each type of training ─ strength training, high intensity and super-maximal interval training, and steady state cardio ─ have their unique benefits and limitations. Using only one of them is like eating only fruits and no vegetables. Don’t fall for any argument that pits one of these methods against another. Have you tried HIIT? Have you been getting good results with it? What other workouts do you include in your weekly routine? Leave a comment below and let us know.

Related: 10 Free Workouts, including HIIT, Plyo and Strength

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