HIIT style workouts are all the rage today. Trainers, the world over, are praising the ‘science’ behind HIIT workouts and their ability to decrease body fat and increase lean muscle. Unfortunately, most trainers are incorrectly interpreting these studies (more on that later). First, let’s define HIIT along with it’s brother and sister, HVIT and VIIT.
- HIIT: High Intensity Interval Training
- HVIT: High Volume Interval Training
- VIIT: Variable Intensity Interval Training
HIIT (High Intensity Interval Training) was designed, and is meant, for individuals pursuing performance improvement, not physical appearance (although, it is a great side effect). This could include a faster 40-yard dash or heavy 1RM on deadlift. With HIIT workouts it is paramount to improvement movement efficiency at the highest levels with exertion rarely falling below 85%. The only way exercises can be performed at this level is with long breaks between sets. A simple math formula to follow in a HIIT workout is 1:2 or 1:3 ratio (30 sec. of work followed by 60 sec. to 90 sec. rest). The counter to these workouts is that you burn fewer calories during the workout. However, the EPOC (after burn) is greater than more intense, continuous interval workouts with shorter rest periods.
HVIT (High Volume Interval Training) is more than likely the type of workout you are performing at a ‘HIIT’ training facility (think crossfit or bootcamp workouts). The emphasis in a HVIT workout is calorie burning (hence the ‘volume’) with shorter rest periods. Put more simply, the more reps you do the greater the calorie burn. It works but at diminishing returns. For example, a standard HVIT workout will have 60 sec. of work w/ 30 sec. of rest. You could burn up to 20 k/min. on the first exercise but will burn 17 on the second, 15 on the third, and so on (these are general numbers). You may feel like your putting everything into each set but that’s merely your aerobic threshold taking over. The energy you used to burn more calories in the first exercise (i.e. phosphogen and glycogen) is depleted. These energy sources can work for upwards of 1-2 min. depending on your fitness level but need upwards of 4-6 min. of recovery time to help you continue at the same level of the first exercise. Calorie burning may be slightly higher than HIIT workouts but your EPOC (after burn) will be lower. In addition, your efficiency in the exercises will become poor as the workout continues leading to injuries that will keep you out of the gym and in bed.
So, where’s the balance? That can be found in what is called VIIT (Variable Intensity Interval Training). The variable being your level of exertion. In other words, you control your intensity level at a better rate because you’ll have longer rest periods than HVIT workouts but at higher intensity levels (but not as high as HIIT workouts). You still get to use your recovery period to burn calories but not greatly tax your phosphogen and glycogen stores. An example of a VIIT workout would be 30 sec. of kettlebell swings followed by 60 sec. of walking, leg swings, hip openers, or light jump roping. The key is to make your ‘active rest’ easy enough that you’ll have enough energy to perform the next exercise efficiently with higher intensity levels.
None of these workouts are better or worse than the next. It is a matter of your personal goals, fitness level, and attention span. If you’re trying to perform better in a sport then HIIT is your bread and butter. Just remember the workouts take longer and are typically ‘boring’. If you’re looking to be entertained, have a short attention span, and want a fast workout with a lot of calorie burning then HVIT workouts are for you. However, your ability to execute the exercises in the workout will degrade and you’ll probably hurt yourself if you’re not careful. Looking for a balance of safety and efficiency? Then go with VIIT.
– Joshua Jarmin – Blueprint Fitness – Owner and Director of Fitness (a.k.a. The Mad Scientist)