When someone says the word ‘cardio’ to you, what comes to mind?
Pounding away on the treadmill?
Using an exercise bike in the gym?
Or perhaps you think of taking in a game of squash with a fellow fitness enthusiast.
The definition of cardio exercise is any form of movement that gets your heart rate up and keeps it there for a period of time. There are many ways that you can do this, however some ways are simply more beneficial than others.
Today we’re going to talk about what may just be the most beneficial cardio method out there: high intensity interval training, also known as HIIT.
What Is Hiit?
High intensity interval training (HIIt) is a form of exercise that gets you alternating between periods of very intense, all out bursts of exercise with active rest periods that are usually one to three times the length.
For example, you might do 30 seconds of exercise, going as hard as you possibly can, and then back off and perform 60 seconds of active rest. Think going from a sprint to a walk.
This is then repeated, 10-20 times (or however long you want), always starting with a brief warm-up and finishing with a cool-down.
Your work intervals will typically range from 15 seconds up to 60 seconds in length, however take note that the shorter the interval, the more intense it should be. If you are doing intervals of 60 seconds, you simply can’t maintain your 15 second interval pace for that long.
This doesn’t mean they will be low intensity, but on a scale of one to ten with ten being the fastest you can possibly go, your 60 second interval may be done at around an 8 where as your 15 second interval will be done at that 10 level.
Choosing your interval length - this will all be based upon your goals.
The more intense the interval, the higher the ratio needs to be.
Use the following as a good guideline for structuring your intervals.
Keep in mind the total number of repetitions you do will be dependent on your overall fitness level, so feel free to adjust those accordingly.
Generally speaking though, these workouts should never be lasting much longer than 15-20 minutes. If they are, that’s a sign you aren’t pushing yourself as hard as you should be during them.
Best HIIT Workout Exercise Examples
This type of training can be done anywhere and usually doesn’t require equipment and may be more efficient in terms of time commitment. This type of training also burns more fat effectively than typical endurance cardio.
Benefits Of High Intensity Interval Training
Now that you know what interval training is, what benefits does it offer? Let’s look at a few of the major advantages of including this workout in your routine.
Fat Loss - you’ll burn more calories not only during the workout, but for hours after the workout is completed due to post-exercise oxygen consumption (EPOC). The end result is you expend calories at an increased pace for up to 48 hours after the workout is completed, giving you an edge on fat burning. Studies showed that when test subjects performed 3 interval sessions per week for 6 weeks, they showed decreases in total body fat percentages, body mass index’s (BMI), as well as waist to hip ratios .
Decreased Gym Time - Because these workouts are so very intense, you’ll be in and out of the gym in no time. Including the warm-up and cool-down, you’ll be looking at no more than 20-30 minutes. A Tabata session is as little as 4 minutes long.
Enhanced Lean Muscle Mass Retention - Many people who diet lose a combination of fat mass as well as lean muscle mass. HIIT can help prevent this. When subjects perform either HIIT or lower intensity, long duration exercise, those who do HIIT lose less muscle overall.
Improved Cardiovascular Fitness Level - With this type of training, you’ll improve your VO2 max level, which represents how much total oxygen your body is able to use during intense physical exercise. As this improves, you’ll notice you become far less fatigued while doing everyday activities.
Reduction In Disease Risk - Regularly performing HIIT will help to lower your blood pressure levels, decrease bad cholesterol levels, and lower your risk for cardiovascular disease. Study  show that after just 3 sessions of less than 10 minutes per week, test subjects were noticing a reduction in disease risk after just a few weeks time.
Advice For Beginners
If you are a beginner who wants to get involved with HIIT cardio training, there’s a specific approach to use. You’ll be best off easing yourself into it, gradually adding an interval or two into your standard cardio session.
Maximum of 2 HIIT workouts per week - Beginners should aim for no more than two HIIT cardio workouts per week to ensure they are giving their body enough recovery time between workouts. Don’t fall into the trap of doing too much, too soon.
Fuel Up Before Each Session - Attempting this on an empty stomach would not be a smart move as your body needs glucose in order to exercise at the intensity you’re going for here. Try a simple snack of around 200 calories about 60 minutes prior to the workout.
Avoid HIIT Workouts Before/After Leg Day - Let’s face it, leg day is hard. Don’t make it any harder on yourself. Avoid doing HIIT on the same day you have a leg workout scheduled. Instead, try and separate them by at least one day for rest.
Gauge Your Recovery Often - Because HIIT workouts are so intense, it’s much easier to overtrain yourself doing it. Be sure to gauge your recovery often. Are you feeling recovered? If the answer is no, you may be doing too much.
Defend Against Injury - Finally, your injury risk during HIIT is much higher due to this intensity. Always watch that you are using good form on whatever exercise you are doing and never skip your warm-ups.
1) MohammadReza Kordi, The effects of six weeks high intensity interval training (HIIT) on resting plasma levels of adiponectin and fat loss in sedentary young women. Retrieved from http://jmj.jums.ac.ir/browse.php?a_id=35&sid=1&slc_lang=en
2) Jenna B. Gillen, Martin J. Gibala, Is high-intensity interval training a time-efficient exercise strategy to improve health and fitness? Retrieved from http://www.nrcresearchpress.com/doi/abs/10.1139/apnm-2013-0187#.WYG4V4iGOUl