Is HIIT Worth the Hype?

Lately, the rage in the fitness world has been all about High Intensity Interval Training, or HIIT. HIIT is an exercise session that alternates periods of short, intense bouts of anaerobic exercise with much less intense recovery periods.  The sessions are shorter than traditional exercise sessions and the interval periods can vary greatly, depending on a person’s fitness level.  The total length of a HIIT session usually lasts anywhere from 4 – 30 minutes. It is used by elite athletes as well as recreational exercisers.
Let’s take a look and see if HIIT is worth all the hype.
The standard way to improve cardiovascular capacity is to do more cardiovascular exercise; run more, cycle more, etc. HIIT has become popular because it is believed to produce the same results as longer endurance exercise sessions in less time.  A 2008 study published in the American Journal of Physiology found that HIIT can produce a large range of physiological gains often in less time than continuous endurance exercise.  A 2007 study in Medicine and Science in Sports and Exercise also produced similar results, claiming that cardiovascular adaptations that appear with HIIT are the same, and, in some cases, superior to continuous steady state training.  
HIIT has even become popular in the healthcare sector.  A 2010 article in Physical Medicine and Rehabilitation stated that interval training is beginning to be implemented in cardiac rehab units. The same improvements were prevalent in patients who performed interval training as those who performed low intensity training, but in a shorter time and fewer sessions.  
Now, that we know the positive changes that take place in the cardiovascular system, what about weight loss? The American Council on Exercise called upon the University of Wisconsin-LaCrosse to test the potential calorie burn of a full body Tabata workout. (Tabata is a form of HIIT that combines 8 cycles of 20 seconds of work with 10 seconds of rest).  The results showed that the participants burned an average of 15 calorie per minute!  These findings support the belief that total body Tabata workouts can improve health and facilitate weight loss.
It looks like HIIT is worth the hype! As you can see, research shows that with HIIT and continuous endurance training, positive improvements are seen in performance, body weight and health.  HIIT is also a time efficient addition to an exercise regime, and can alleviate boredom.  There are many options to choose from; you can find on line workouts, you can make up your own, or use the ones below. Whatever you choose be consistent with your workouts and results will follow.
Following are 2 examples of HIIT workouts:
Treadmill Workout
Warm up: 10 mins walk or light jog
Work interval: run 1 min at 5 mph – 1 min at 6mph – 1 min at 7mph; 3 % incline grade for all intervals.
Rest interval: Walk 1 min at 4 mph; 3% incline grade
Repeat this work interval-rest interval sequence 5 – 8 times.
Cool down: 5 – 10 mins of a light jog to a gradual walk.
The times, speeds and incline in this routine can be adjusted up or down according to you fitness level.
Tabata Workout
This is the 20 min Tabata workout from the study performed by the U of W, cited above. A set of each exercise is 20 seconds of work, followed by 10 seconds of rest. One minute of rest should be taken between each round.
Round 1 (4 mins): 2 sets of high knees – 2 sets of plank punches – 2 sets of jumping jacks – 2 sets of side skaters – Rest
Round 2 (4 mins): 2 sets jump rope   – 2 sets high/low boat (sit in a v position, upper body & legs off floor, extend legs out and slightly drop upper body towards the floor, come up and repeat) – 2 sets line jumps – 2 sets pushups – Rest
Round 3 (4 mins): 2 sets burpees – 2 sets Russian twists – 2 sets squats – 2 sets lunges – Rest
Round 4 (4 mins): 2 sets mountain climbers – 2 sets pushups – 2 sets split squats – 2 sets box jumps

HIIT tips:
This type of training is not for beginners.  A fitness program should begin with low intensity continuous training and progress slowly to interval training.  Jumping into this type of program can increase the risk of injury.  When you can comfortably do 30 minutes of continuous cardio exercise at a moderate pace, start introducing intervals into your program.
This intense type of exercise should not be done every day. Research shows that 3 days per week is the most effective for producing results and limiting injuries.  Low to moderate intensity, longer duration workouts are very effective and should still be part of your fitness regime.  HIIT is an alternative, not a replacement for, traditional endurance style programs.