Recently high intensity interval training (HIIT) routines have become more and more popular as an alternative to traditional steady state cardio (running, cycling, swimming etc. for more than 20 minutes at a steady intensity/pace) but what exactly is HIIT?

     Simply put HIIT is a combination of high intensity bouts of exercise coupled with low intensity rest periods done back and forth for a set number of rounds, distance or time. Though this training style is just now getting more recognition it has been around since at least the early 1900’s and possibly longer. Because the definition of HIIT is relatively vague, there are many different programs that fall under this category. The main determining factor for choosing or designing a HIIT program will be your goals, as different work to rest ratios and forms of exercise will have very different outcomes. Here are a few basic examples of workouts that fall under HIIT routines.

Here are some of our favorite HIIT workout videos here on Fitness Blender:

• 40 Minute Brutal HIIT Workout Game: Fat Burning Ladder, Pyramid and Tabata HIIT at Home​ (Difficulty 5/5)
• 17 MInute Fat Burning HIIT Workout - HIIT Cardio with Warm Up (with Low Impact Modifications) (Difficulty 4/5)
• 15 Minute HIIT Metabolism Booster - Total Body and Abs HIIT Workout​ (Difficulty 4/5)
• 52 Minute Strength, HIIT & Pilates Workout for a Bigger Butt & Strong Legs - Lower Body Burnout​ (5/5)
• Fitness Blender's 5 Day Challenge - Strong and Lean - Day 1 (HIIT & Butt & Thigh Workout) (Difficulty 3-4/5)

Interval Program 1:
Cardio Machine Intervals (treadmill, elliptical, arch trainer, step machine, etc)

Warm-up: 10-15 minutes working up from low to medium intensity ending with at least 5 minutes at a 4-6 rate of perceived exertion (RPE).

Work Interval: Increase as rapidly as is comfortable to an 8-9 RPE using a combination incline, resistance, and/or speed. Hold at this rate for one minute.

Rest Interval: Drop down to a RPE of 4-5 and hold for two minutes.

Work-to-rest ratio: 1:2

Rounds: Repeat for 5-8 rounds

Cool-down: 5-10 minutes of an easy level of exertion


Interval Program 2:
Cardio/Strength Training (done with a prebuilt routine of plyometric/high intensity total body exercises).

Warm-up: 10-15 minutes of light cardio; running, jogging, jumping jacks, etc.

Work Interval: 20 seconds of 90-100% of maximum effort

Rest Interval: 10 seconds non-activity or very light walking or jogging in place.

Work-to-rest ratio: 2:1

Rounds:
Option A: 2 rounds each of 4 exercises; repeat total group twice.
Option B: 1-4 rounds per exercise with a total of 4-12 exercises one time through.

Cool-down: 5-10 minutes of light cardio; jogging, walking, etc.


Interval Program 3:
Track Workout (needs to be done on a track or trail not on a treadmill)

Warm-up: 10-15 minutes of light running/jogging

Work Interval: 800-meter run at around 90% or maximum exertion. Interval should be timed (time will change with each work interval).

Rest Interval: Walk or slow jog for same time taken to complete previous 800-meter (time will change with changing time taken to complete previous 800-meter)

Work-to-rest ratio: 1:1

Rounds: 2-5 Rounds

Cool-down: Walk for 5-10 minutes


How many calories does HIIT burn?
     High intensity interval training burns more calories than steady state cardio for two reasons. For one, it is completed at a more intense rate of exertion than can possibly be maintained for a longer duration workout (i.e. the pace one holds for a 30-60 stable paced minute jog), meaning that you expend more calories per minute.

     In addition, HIIT is intense enough that it causes a metabolic disturbance that your body has to recover from – that recovery involves 24-48 hours of an elevated metabolism (meaning you burn calories at a higher rate even while resting). Steady rate cardio does not provide that metabolism boost, at the very least, not nearly as well as higher intensity interval training does.

How often should I do HIIT Cardio Workouts?
     Your body needs time to heal itself after this kind of training, so it is not recommended that you use it more than 3 times a week.

Other benefits of HIIT
-Reduced insulin resistance
-Better cardiac function
-Faster metabolism
-Produces faster gains in endurance levels than steady state cardio
-Effective way to recruit/build type 2 Fast Twitch muscle
-Can be done anywhere; usually don’t require equipment
-Efficient in terms of time commitment
-Burns fat more effectively than endurance cardio

Fitness Blender has many, many free full length HIIT workout videos, check them out!